RFR: 8342808: Javadoc should add whitespace between type parameters [v3]

[Nizar Benalla]

> Please review this patch to render javadocs as `<K, V, T>` rather than `<K,V,T>` to match naming conventions and make the rendered output slighly nicer to read.
> 
> Passes langtool tests.
> 
> The [generated docs](https://cr.openjdk.org/~nbenalla/GeneratedDocs/K-V-space/docs/api/index.html) only include `java.base`.
> 
> Note for reviewers:
> 
> In `TestInheritence`, B is a user defined class and `TypeMirror::getKind` returns `DECLARED `. Which why we see this output. 
> 
> 
> 
> html
> 
> Class D<R,S>
> java.lang.Object
> [pkg.A](https://htmledit.squarefree.com/A.html)<S, [B](https://htmledit.squarefree.com/B.html)>
> [pkg.B](https://htmledit.squarefree.com/B.html)<S, [B](https://htmledit.squarefree.com/B.html)>
> pkg.D<R,S>

Nizar Benalla 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 five additional commits since the last revision:

 - use a simpler approach to decide whether to add spaces or not
   
   remove code related to adding new lines for very long methods (only used a couple of times in the JDK)
 - Merge remote-tracking branch 'upstream/master' into javadoc-whitespace
 - small improvement after getting review comments.
   
   Update tests
 - Merge remote-tracking branch 'upstream/master' into javadoc-whitespace
 - Add small whitespace before map parameters

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

Changes:
  - all: https://git.openjdk.org/jdk/pull/21759/files
  - new: https://git.openjdk.org/jdk/pull/21759/files/81ced388..31fb008f

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=21759&range=02
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=21759&range=01-02

  Stats: 69434 lines in 1062 files changed: 31085 ins; 34149 del; 4200 mod
  Patch: https://git.openjdk.org/jdk/pull/21759.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/21759/head:pull/21759

PR: https://git.openjdk.org/jdk/pull/21759