RFR: 8222329: Readable read(CharBuffer) does not specify that 0 is returned when there is no remaining space in buffer [v5]

[Brian Burkhalter]

> Clarify the behavior of `java.lang.Readable` when the specified `java.nio.CharBuffer` parameter is empty but read-only, and when it is full.

Brian Burkhalter has updated the pull request incrementally with one additional commit since the last revision:

  8222329: Tweak verbiage some more

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Changes:
  - all: https://git.openjdk.org/jdk/pull/14616/files
  - new: https://git.openjdk.org/jdk/pull/14616/files/d693c612..94505a45

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=14616&range=04
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=14616&range=03-04

  Stats: 10 lines in 3 files changed: 3 ins; 0 del; 7 mod
  Patch: https://git.openjdk.org/jdk/pull/14616.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/14616/head:pull/14616

PR: https://git.openjdk.org/jdk/pull/14616