[hide_input] update readme

in light of [ipython-contrib#740](ipython-contrib#740)

src/jupyter_contrib_nbextensions/nbextensions/hide_input/readme.md

@@ -1,31 +1,70 @@
 Hide Input
 ==========
-This extension allows hiding of an individual codecell in a notebook. This can be achieved by clicking on the toolbar 
-button:
+
+This extension allows hiding of an individual codecell in a notebook. This can
+be achieved by clicking on the toolbar button:
+
 ![](icon.png)
 
+
 Internals
 ---------
 
 The codecell hiding state is stored in the metadata `cell.metadata.hide_input`.
 If it is set to `true`, the codecell will be hidden on reload.
 
-To export a notebook with hidden cells using nbconvert, you need to add a custom template and a custom filter:
-```
+
+Exporting with nbconvert
+------------------------
+
+See also the general docs for exporting using nbconvert at
+[jupyter-contrib-nbextensions.readthedocs.io](http://jupyter-contrib-nbextensions.readthedocs.io/en/latest).
+
+To export a notebook with hidden cell inputs using nbconvert, you need to use a
+custom template and a custom filter.
+The required filter and template are supplied as part of
+`jupyter_contrib_nbextensions.nbconvert_support`, or you can roll your own
+using the provided ones as examples. Again, see the docs linked above for more
+information.
+
+The `nbextensions.tpl` template is provided in the
+`jupyter_contrib_nbextensions.nbconvert_support` templates directory (see the
+docs mentioned above for how to find it), while the necessary
+`strip_output_prompt` filter, is provided by
+`jupyter_contrib_nbextension.nbconvert_support.strip_output_prompt`.
+
+An example of a python config file which will arrange to use the correct
+template and filter:
+
+```python
+import os
+import jupyter_contrib_nbextensions.nbconvert_support
+
 c = get_config()
-c.Exporter.template_file = 'nbextensions'
-c.Exporter.filters = {'strip_output_prompt': 'strip_output_prompt.strip_output_prompt'}
+c.Exporter.template_file = os.path.join(
+    jupyter_contrib_nbextensions.nbconvert_support.templates_directory(),
+    'nbextensions')
+c.Exporter.setdefault('filters', {})['strip_output_prompt'] = (
+    'jupyter_contrib_nbextensions.nbconvert_support.'
+    'strip_output_prompt.strip_output_prompt')
 ```
 
-The template will respect the `cell.metadata.hide_input` flag, and the filter will remove the cell output prompt 
-that looks like `Out[27]:`. The filter is not used for PDF or LaTeX output.
+To use, put this config into a file named `jupyter_nbconvert_config.py` in the
+same directory as the notebook you wish to convert, and call using
+
+    nbconvert --config=jupyter_nbconvert_config.py my_notebook.ipynb
+
+The nbextensions template will respect the `cell.metadata.hide_input` flag, and
+the filter will remove the cell's output prompt (the bit that looks like
+`Out[27]:`).
+The filter is only used for html output, not for PDF or LaTeX output.
+
+If you want to _keep_ the cell output prompt, you will have to change the line
+
+    {{ super() | strip_output_prompt }}
 
-If you want to keep the cell output prompt, you will have to change the line
-```
-   {{ super() | strip_output_prompt }}
-```
 to
-```
-   {{ super() }}
-```
-in the `nbextensions.tpl` file. 
+
+    {{ super() }}
+
+in the `nbextensions.tpl` file.