RFR: JDK-8305713: DocCommentParser: merge blockContent and inlineContent

[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.

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Depends on: https://git.openjdk.org/jdk/pull/13362

Commit messages:
 - JDK-8305713: DocCommentParser: merge blockContent and inlineContent
 - 8272119: Typo in JDK documentation (a -> an)
 - 8305461: [vectorapi] Add VectorMask::xor
 - 8305608: Change VMConnection to use "test.class.path"instead of "test.classes"
 - 8274166: Some CDS tests ignore -Dtest.cds.runtime.options
 - 8304745: Lazily initialize byte[] in java.io.BufferedInputStream
 - 8267140: Support closing the HttpClient by making it auto-closable
 - 8269843: typo in LinkedHashMap::removeEldestEntry spec
 - 8305480: test/hotspot/jtreg/runtime/NMT/VirtualAllocCommitMerge.java failing on 32 bit arm
 - 8305607: Remove some unused test parameters in com/sun/jdi tests
 - ... and 6 more: https://git.openjdk.org/jdk/compare/44f33ad1...b8b43eae

Changes: https://git.openjdk.org/jdk/pull/13431/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=13431&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8305713
  Stats: 5934 lines in 119 files changed: 5071 ins; 480 del; 383 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