RFR: 8250659: Clarify in ParameterizedType.getRawType() doc that only Class is returned [v2]

[Chen Liang]

> Clarify that only `Class` is returned for core reflection implementation, and the return type is `Type` to support other implementations, such as ones modeling unloaded or remote types.

Chen Liang 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 three additional commits since the last revision:

 - Reword
 - Merge branch 'master' of https://github.com/openjdk/jdk into doc/raw-type
 - 8250659: Clarify in ParameterizedType.getRawType() doc that only Class is returned

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Changes:
  - all: https://git.openjdk.org/jdk/pull/19978/files
  - new: https://git.openjdk.org/jdk/pull/19978/files/ab617da5..e9ca21a9

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=19978&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=19978&range=00-01

  Stats: 435100 lines in 4440 files changed: 368107 ins; 41407 del; 25586 mod
  Patch: https://git.openjdk.org/jdk/pull/19978.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/19978/head:pull/19978

PR: https://git.openjdk.org/jdk/pull/19978