RFR: JDK-8305713: DocCommentParser: merge blockContent and inlineContent [v4]

[Jonathan Gibbons]

> Please review a cleanup in DocCommentParser to merge blockContent and inlineContent into a single method to parse "rich content" in a doc comment.
> 
> **Note:** This is dependent on PR #13362, to convert `DocCommentParser` to use enhanced switch.

Jonathan Gibbons has updated the pull request with a new target base due to a merge or a rebase. The pull request now contains eight commits:

 - Merge
 - Merge branch 'pr/13362' into pr/13362
 - convert additional switch statements
 - JDK-8305673: Convert DocCommentParser to use enhanced switch
 - avoid conflict with dependent PR
 - Merge remote-tracking branch 'upstream/master' into 8305713.dcp-content
 - Merge remote-tracking branch 'upstream/master' into 8305713.dcp-content
 - JDK-8305713: DocCommentParser: merge blockContent and inlineContent

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Changes: https://git.openjdk.org/jdk/pull/13431/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=13431&range=03
  Stats: 336 lines in 1 file changed: 100 ins; 131 del; 105 mod
  Patch: https://git.openjdk.org/jdk/pull/13431.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/13431/head:pull/13431

PR: https://git.openjdk.org/jdk/pull/13431