RFR: 8306431: File.listRoots method description should be re-examined [v4]

[Nagata-Haruhito]

> I fixed File.listRoots description.
> * remove "the insertion or ejection of removable media"
> * change "available" to "existing"
> 
> Please review this change.

Nagata-Haruhito 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:

 - Merge branch 'openjdk:master' into File_javadoc
 - 8306431: The documentation of File.listRoots should be modifid after JDK-8208077
 - 8306431: File.listRoots method description should be re-examined

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

Changes:
  - all: https://git.openjdk.org/jdk/pull/13526/files
  - new: https://git.openjdk.org/jdk/pull/13526/files/ef38a529..acb639e5

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=13526&range=03
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=13526&range=02-03

  Stats: 233660 lines in 1515 files changed: 217436 ins; 6745 del; 9479 mod
  Patch: https://git.openjdk.org/jdk/pull/13526.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/13526/head:pull/13526

PR: https://git.openjdk.org/jdk/pull/13526