improvement(api-markdown-documenter): Don't support LineBreakNodes as BlockContent

[Josmithr]

Block Content items are implicitly separated by a line break, so allowing LineBreakNodes in that context is redundant and was not needed.
Support for LineBreakNodes in BlockContent contexts has been removed.

[Copilot]

Pull Request Overview

This PR removes support for the redundant LineBreakNode in BlockContent contexts. The changes include eliminating the LineBreakNode import and its mapping in BlockContent, removing filtering logic for adjacent line breaks in TsdocNodeTransforms, and updating the API reports, package version, and changelog.

Reviewed Changes

Copilot reviewed 7 out of 7 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
tools/api-markdown-documenter/src/documentation-domain/BlockContent.ts	Removed LineBreakNode import and mapping from the BlockContentMap.
tools/api-markdown-documenter/src/api-item-transforms/TsdocNodeTransforms.ts	Replaced mutation with a const declaration and removed redundant filtering logic and the now-unused helper function.
tools/api-markdown-documenter/api-report/api-markdown-documenter.public.api.md	Removed the LineBreakNode entry from the public API report.
tools/api-markdown-documenter/api-report/api-markdown-documenter.beta.api.md	Removed the LineBreakNode entry from the beta API report.
tools/api-markdown-documenter/api-report/api-markdown-documenter.alpha.api.md	Removed the LineBreakNode entry from the alpha API report.
tools/api-markdown-documenter/package.json	Updated the package version to reflect the changes.
tools/api-markdown-documenter/CHANGELOG.md	Added a changelog entry documenting the removal of LineBreakNode from BlockContent.

Comments suppressed due to low confidence (8)

tools/api-markdown-documenter/src/documentation-domain/BlockContent.ts:8

• Removal of the LineBreakNode import from BlockContent.ts is consistent with the design change; please confirm that no other dependent logic requires this type.

import type { LineBreakNode } from "./LineBreakNode.js";

tools/api-markdown-documenter/src/api-item-transforms/TsdocNodeTransforms.ts:108

• The shift from a mutable to an immutable declaration and the removal of redundant new line filtering improves code clarity.

let transformedChildren: BlockContent[] = [];

tools/api-markdown-documenter/src/api-item-transforms/TsdocNodeTransforms.ts:472

• Removal of the filterNewlinesAdjacentToParagraphs function is appropriate given that LineBreakNodes are no longer supported; ensure tests cover this change.

function filterNewlinesAdjacentToParagraphs(nodes: readonly BlockContent[]): BlockContent[] { ... }

tools/api-markdown-documenter/api-report/api-markdown-documenter.public.api.md:168

• Removal of the LineBreakNode mapping in the public API report aligns with the updated design.

lineBreak: LineBreakNode;

tools/api-markdown-documenter/api-report/api-markdown-documenter.beta.api.md:168

• Removing the LineBreakNode mapping from the beta API report is consistent with the overall removal of support.

lineBreak: LineBreakNode;

tools/api-markdown-documenter/api-report/api-markdown-documenter.alpha.api.md:168

• Removal of the LineBreakNode mapping in the alpha API report is consistent with the updated design.

lineBreak: LineBreakNode;

tools/api-markdown-documenter/package.json:3

• The version bump to 0.21.0 is appropriate and reflects the changes made; ensure that related documentation and tests are updated accordingly.

"version": "0.21.0",

tools/api-markdown-documenter/CHANGELOG.md:3

• The changelog entry clearly documents the removal of LineBreakNode from BlockContent; ensure consistency in all release notes.

## 0.21.0

[github-actions]

🔗 No broken links found! ✅

Your attention to detail is admirable.

linkcheck output

> fluid-framework-docs-site@0.0.0 ci:check-links /home/runner/work/FluidFramework/FluidFramework/docs
> start-server-and-test "npm run serve -- --no-open" 3000 check-links

1: starting server using command "npm run serve -- --no-open"
and when url "[ 'http://127.0.0.1:3000' ]" is responding with HTTP status code 200
running tests using command "npm run check-links"


> fluid-framework-docs-site@0.0.0 serve
> docusaurus serve --no-open

[SUCCESS] Serving "build" directory at: http://localhost:3000/

> fluid-framework-docs-site@0.0.0 check-links
> linkcheck http://localhost:3000 --skip-file skipped-urls.txt

Crawling...

Stats:
  222981 links
    1707 destination URLs
    1939 URLs ignored
       0 warnings
       0 errors