fix: update Prismic terms to use the latest language style

[angeloashmore]

Types of changes

• Chore (a non-breaking change which is related to package maintenance)
• Bug fix (a non-breaking change which fixes an issue)
• New feature (a non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)

Description

This PR updates documentation and APIs to use the latest field name styles.

The following changes are included:

• "Integration Fields" → "integration" (e.g. "An integration field")
• "Custom Type" → "custom type" (e.g. "A custom type model")
• "Shared Slice" → "shared Slice" (e.g. "A shared Slice model")
• Lowercase all field names (e.g. "Rich Text" → "rich text")

Integration fields

This package exports APIs that use the terms IntegrationFields and integrationFields. This PR deprecates, not removes, those APIs in favor of the renamed versions.

Please see the changed files for a full list of deprecated APIs.

cc @samlfair

Checklist:

• My change requires an update to the official documentation.
• All TSDoc comments are up-to-date and new ones have been added where necessary.
• All new and existing tests are passing.

🦮

[codecov-commenter]

Codecov Report

Merging #293 (1740d2d) into v7 (b4bdf7f) will increase coverage by 0.00%.
The diff coverage is 100.00%.

❗ Your organization is not using the GitHub App Integration. As a result you may experience degraded service beginning May 15th. Please install the Github App Integration for your organization. Read more.

@@           Coverage Diff           @@
##               v7     #293   +/-   ##
=======================================
  Coverage   99.94%   99.94%           
=======================================
  Files          49       49           
  Lines        5697     5722   +25     
  Branches      302      303    +1     
=======================================
+ Hits         5694     5719   +25     
  Misses          3        3           

Impacted Files	Coverage Δ
src/buildQueryURL.ts	99.46% <100.00%> (ø)
src/createClient.ts	100.00% <100.00%> (ø)
src/filter.ts	100.00% <100.00%> (ø)
src/helpers/asDate.ts	100.00% <100.00%> (ø)
src/helpers/asHTML.ts	100.00% <100.00%> (ø)
src/helpers/asImagePixelDensitySrcSet.ts	100.00% <100.00%> (ø)
src/helpers/asImageSrc.ts	100.00% <100.00%> (ø)
src/helpers/asImageWidthSrcSet.ts	100.00% <100.00%> (ø)
src/helpers/asLink.ts	100.00% <100.00%> (ø)
src/helpers/asLinkAttrs.ts	100.00% <100.00%> (ø)
... and 11 more

[lihbr]

Will have a look at it :)

Just letting you know, you can change the target branch of a PR after it's opened if need be~

[lihbr]

LGTM for the deprecation part, thanks for taking care of that! 👌