<i18n dev> RFR: 8364365: HKSCS encoder does not properly set the replacement character [v3]

[Volkan Yazici]

> Fix `HKSCS` encoder to correctly set the replacement character, and add tests to verify the `CodingErrorAction.REPLACE` behavior of all available encoders.

Volkan Yazici has updated the pull request incrementally with one additional commit since the last revision:

  Improve pretty-printers

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Changes:
  - all: https://git.openjdk.org/jdk/pull/26635/files
  - new: https://git.openjdk.org/jdk/pull/26635/files/f567f2c8..f056028a

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=26635&range=02
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=26635&range=01-02

  Stats: 14 lines in 1 file changed: 2 ins; 6 del; 6 mod
  Patch: https://git.openjdk.org/jdk/pull/26635.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/26635/head:pull/26635

PR: https://git.openjdk.org/jdk/pull/26635