RFR: 8325168: JShell should support Markdown comments [v2]

[Jan Lahoda]

> This is an attempt to add Markdown support in documentation comments to JShell.
> 
> It works by converting the Markdown text to HTML during the process of resolving `{@inheritDoc}` tags.

Jan Lahoda has updated the pull request with a new target base due to a merge or a rebase. The pull request now contains 15 commits:

 - Post merge fix.
 - Merge branch '8298405.doclet-markdown-v3' into JDK-8298405
 - Cleanup.
 - Preventing a NPE.
 - Fixing test.
 - Merge branch '8298405.doclet-markdown-v3' into JDK-8298405
 - Cleanup.
 - Merge branch '8298405.doclet-markdown-v3' into JDK-8298405
 - Cleanup.
 - Merge branch '8298405.doclet-markdown-v3' into JDK-8298405
 - ... and 5 more: https://git.openjdk.org/jdk/compare/e48ebb53...28211c75

-------------

Changes: https://git.openjdk.org/jdk/pull/17686/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=17686&range=01
  Stats: 1824 lines in 8 files changed: 977 ins; 842 del; 5 mod
  Patch: https://git.openjdk.org/jdk/pull/17686.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/17686/head:pull/17686

PR: https://git.openjdk.org/jdk/pull/17686