RFR: JDK-8307184: Incorrect/inconsistent specification and implementation for Elements.getDocComment

[Joe Darcy]

Start by just reformatting the existing specs to highlight subsequent spec changes.

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Commit messages:
 - JDK-8307184: Incorrect/inconsistent specification and implementation for Elements.getDocComment

Changes: https://git.openjdk.org/jdk/pull/15062/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=15062&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8307184
  Stats: 8 lines in 1 file changed: 5 ins; 0 del; 3 mod
  Patch: https://git.openjdk.org/jdk/pull/15062.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/15062/head:pull/15062

PR: https://git.openjdk.org/jdk/pull/15062