RFR: 8306431: File.listRoots method description should be re-examined [v5]

[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 four additional commits since the last revision:

 - Merge branch 'openjdk:master' into File_javadoc
 - 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/acb639e5..787f71a1

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=13526&range=04
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=13526&range=03-04

  Stats: 176489 lines in 2827 files changed: 134200 ins; 21560 del; 20729 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