[DOCS] Adds 8.8 Viz docs (elastic#157215)

## Summary

Adds the 8.8 documentation for the following:

- Enable report sharing: elastic#153429
Docs preview:
https://kibana_157215.docs-preview.app.elstc.co/guide/en/kibana/master/reporting-getting-started.html

- Random sampling feature: elastic#143221
Docs preview:
https://kibana_157215.docs-preview.app.elstc.co/guide/en/kibana/master/lens.html#improve-visualization-loading-time

- Improve Ignore global filters UI:
elastic#154441 and
elastic#155280
Docs preview:
https://kibana_157215.docs-preview.app.elstc.co/guide/en/kibana/master/lens.html#add-annotations

---------

Co-authored-by: Tim Sullivan <tsullivan@users.noreply.github.com>
(cherry picked from commit 06a800f)

docs/user/dashboard/lens.asciidoc

@@ -175,18 +175,35 @@ Compare your real-time data to the results that are offset by a time increment.
 For a time shift example, refer to <<compare-time-ranges>>.
 
 [float]
-[[multi-metric-partition-chart]]
-==== Build a partition chart from multiple metrics
+[[create-partition-charts-with-multiple-metrics]]
+==== Create partition charts with multiple metrics
 
-By default, partition charts (e.g. pie) are built from one or more "slice-by" dimensions to define the partitions and a single metric dimension to define their size. However, you can also build a partition chart from multiple metric dimensions.
+To create partition charts, such as pie charts, configure one or more *Slice by* dimensions to define the partitions, and a *Metric* dimension to define the size. 
+To create partition charts with multiple metrics, use the layer settings. Multiple metrics are unsupported for mosaic visualizations.
 
-. Open the layer context menu at the top right of the layer panel.
+. In the layer pane, click image:dashboard/images/lens_layerActions_8.5.0.png[Actions menu for the partition visualization layer], then select *Layer settings*.
 
-. Click *Layer settings*.
+. Select *Multiple metrics*.
 
-. Click the switch labeled *Multiple metrics*.
+. Click *X*.
 
-Note: this option is not available for mosaic charts.
+[float]
+[[improve-visualization-loading-time]]
+=== Improve visualization loading time
+
+preview::[]
+
+Data sampling allows you to improve the visualization loading time. To decrease the loading time, use a lower sampling percentage, which also decreases the accuracy. 
+Use low sampling percentages on large datasets.
+
+. In the layer pane, click image:dashboard/images/lens_layerActions_8.5.0.png[Actions menu for the partition visualization layer], then select *Layer settings*.
+
+. To select the *Sampling* percentage, use the slider.
+
+. Click *X*.
++
+When you add the visualization to dashboards, image:dashboard/images/lens_visualizationModifierPopup_8.8.0.png[Visualization modifier popup] appears, 
+which allows you to view settings changes to the visualization.
 
 [float]
 [[add-annotations]]
@@ -214,6 +231,9 @@ Create the annotation layer.
 . From the fields list, drag a field to the *Add an annotation* field.
 
 . To use global filters in the annotation, click image:dashboard/images/lens_layerActions_8.5.0.png[Actions menu for the annotations layer], then select *Keep global filters* from the dropdown.
++
+When you add the visualization to dashboards, image:dashboard/images/lens_visualizationModifierPopup_8.8.0.png[Visualization modifier popup] appears, 
+which allows you to view settings changes to the visualization.
 
 Create static annotations.
 

docs/user/reporting/index.asciidoc

@@ -13,19 +13,21 @@
 
 You access the options from the *Share* menu in the toolbar. The sharing options include the following:
 
-* *PDF Reports* — Generate and download a PDF file of a dashboard, visualization, or *Canvas* workpad. PDF reports are a link:https://www.elastic.co/subscriptions[subscription feature].
+* *PDF Reports* — Generate and download PDF files of dashboards, visualizations, and *Canvas* workpads. PDF reports are a link:https://www.elastic.co/subscriptions[subscription feature].
 
-* *PNG Reports* — Generate and download a PNG file of a dashboard or visualization. PNG reports are a link:https://www.elastic.co/subscriptions[subscription feature].
+* *PNG Reports* — Generate and download PNG files of dashboards and visualizations. PNG reports are a link:https://www.elastic.co/subscriptions[subscription feature].
 
-* *CSV Reports* — Generate and download a CSV file of a *Discover* saved search.
+* *CSV Reports* — Generate and download CSV files of saved searches.
 
-* *Get links* — Share a direct link to a *Discover* saved search, dashboard, or visualization.
+* *CSV Download* — Generate and download CSV files of *Lens* visualizations.
 
-* *Download as JSON* — Generate and download a JSON file of a *Canvas* workpad.
+* *Get links* — Share direct links to saved searches, dashboards, and visualizations.
+
+* *Download as JSON* — Generate and download JSON files of *Canvas* workpads.
 
 * beta[] *Share on a website* — Download and securely share *Canvas* workpads on any website.
 
-* *Embed code* — Embed a fully interactive dashboard as an iframe on a web page.
+* *Embed code* — Embed fully interactive dashboards as an iframe on web pages.
 
 [[reporting-on-cloud-resource-requirements]]
 NOTE: For Elastic Cloud deployments, {kib} instances require a minimum of 2GB RAM to generate PDF or PNG reports. To
@@ -51,19 +53,13 @@ image::user/reporting/images/shareable-container.png["Shareable Container"]
 
 . Open the main menu, then open the saved search, dashboard, visualization, or workpad you want to share.
 
-. From the toolbar, click *Share*, then select one of the following options:
-
-** **PDF Reports** — Generates a PDF file of the dashboard, visualization, or workpad.
-
-** **PNG Reports** — Generates a PNG file of the dashboard or visualization.
+. From the toolbar, click *Share*, then select the report option. 
 
-** **CSV Reports** — Generates a CSV report of the saved search.
-
-. If you are creating a PDF report of a dashboard, select *Optimize for printing* to create a printer-friendly PDF with multiple A4 portrait pages and two visualizations per page.
+* If you are creating dashboard PDFs, select *Optimize for printing* to create printer-friendly PDFs with multiple A4 portrait pages and two visualizations per page.
 +
 NOTE: When you create a dashboard report that includes a data table or saved search, the PDF includes only the visible data.
 
-. If you are creating a PDF report of a workpad, select *Full page layout* to create a PDF without margins that surround the workpad.
+* If you are creating workpad PDFs, select *Full page layout* to create PDFs without margins that surround the workpad.
 
 . Generate the report.
 
@@ -78,9 +74,9 @@ more about {ilm-init} policies, refer to the {es}
 
 [float]
 [[share-a-direct-link]]
-== Share a direct link
+== Share direct links
 
-Share a direct link to a saved search, dashboard, or visualization. To access the shared object, authentication is required.
+Create and share direct links to saved searches, dashboards, and visualizations. To access the shared object, authentication is required.
 
 . Open the main menu, then open the saved search, dashboard, or visualization you want to share.
 
@@ -105,9 +101,9 @@ NOTE: *Public URL* is available only when anonymous access is configured and you
 
 [float]
 [[download-as-json]]
-== Create a JSON file
+== Create JSON files
 
-Create a JSON file for a workpad.
+Create and share JSON files for workpads.
 
 . Open the main menu, then click *Canvas*.
 
@@ -119,17 +115,14 @@ Create a JSON file for a workpad.
 [[add-workpad-website]]
 == Share workpads on a website
 
-beta[] *Canvas* allows you to create _shareables_, which are workpads that you download and securely share on a website.
-To customize the behavior of the workpad on your website, you can choose to autoplay the pages or hide the workpad toolbar.
+beta[] Create and securely share static *Canvas* workpads on a website. To customize the behavior of the workpad on your website, you can choose to autoplay the pages or hide the workpad toolbar.
 
 . Open the main menu, then click *Canvas*.
 
 . Open the workpad you want to share.
 
 . Click *Share > Share on a website*.
 
-. Follow the instructions.
-
 . To customize the workpad behavior to autoplay the pages or hide the toolbar, use the inline parameters.
 +
 To make sure that your data remains secure, the data in the JSON file is not connected to {kib}. *Canvas* does not display elements that manipulate the data on the workpad.
@@ -142,21 +135,21 @@ NOTE: Shareable workpads encode the current state of the workpad in a JSON file.
 [[embed-code]]
 == Embed code
 
-Display your dashboard on an internal company website or personal web page with an iframe. Embedding other {kib} objects is generally supported, but you might need to manually craft the proper HTML code.
+Display your dashboards on an internal company website or personal web page with an iframe. To embed other {kib} objects, manually create the HTML code.
 
-Some users might not have access to the dashboard or visualization. For more information, refer to <<anonymous-access-and-embedding>> and <<embedded-content-authentication>>.
+For information about granting access to embedded dashboards, refer to <<kibana-authentication>>.
 
 . Open the main menu, then open the dashboard you want to share.
 
 . Click *Share > Embed code*.
 
 . Specify how you want to generate the code:
 
-* To display only the current state, select *Snapshot*.
+* To display the current state, select *Snapshot*.
 
 * To display up-to-date changes, select *Saved object*.
 
-* Select the dashboard components you want to include.
+* Select the dashboard components you want to share.
 
 * To generate a shortened link, select *Short URL*.