RFR: 8285470: Improve handling of @inheritDoc [v4]

[Pavel Rappo]

> The only taglet that along with its own tag needs to know the immediately enclosing tag is `InheritDocTaglet`:
> 
>     @return {@inheritDoc}
>     @throws NullPointerException {@inheritDoc}
>     @param p {@inheritDoc}
> 
> However, the immediately enclosing tag is unconditionally passed to all taglets. If we stop passing it and make `InheritDocTaglet` compute it instead, the code becomes cleaner.
> 
> While reviewing, particularly note these benefits of the proposed change:
> 
>  * taglet-handling code knows less about `@inheritDoc`, and
>  * `InheritDocTaglet` receives its own tag, not the tag that encloses it

Pavel Rappo has updated the pull request with a new target base due to a merge or a rebase. The incremental webrev excludes the unrelated changes brought in by the merge/rebase. The pull request contains ten additional commits since the last revision:

 - Merge branch 'master' into 8285470
 - (feedback) typography
 - Update src/jdk.javadoc/share/classes/jdk/javadoc/internal/doclets/toolkit/taglets/InheritDocTaglet.java
   
   Co-authored-by: ExE Boss <3889017+ExE-Boss at users.noreply.github.com>
 - (fix) Fix a test failure
   
   Fixes a failure in jdk/javadoc/doclet/testInheritDocWithinInappropriateTag/TestInheritDocWithinInappropriateTag.java
 - (cleanup) Simplify retrieveInheritedDocumentation
 - (cleanup) Clarify retrieveInheritedDocumentation
 - (cleanup) Unify specs of commentTagsToContent
 - Stop passing "holderTag"
 - (cleanup) Remove useless null check
   
   DocFinder.search cannot return null.

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

Changes:
  - all: https://git.openjdk.java.net/jdk/pull/8361/files
  - new: https://git.openjdk.java.net/jdk/pull/8361/files/8bf226f7..31721e9d

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=jdk&pr=8361&range=03
 - incr: https://webrevs.openjdk.java.net/?repo=jdk&pr=8361&range=02-03

  Stats: 27873 lines in 776 files changed: 19631 ins; 3824 del; 4418 mod
  Patch: https://git.openjdk.java.net/jdk/pull/8361.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/8361/head:pull/8361

PR: https://git.openjdk.java.net/jdk/pull/8361