RFR: 8341560: Better documentation for KeyCombinations/KeyCodes/KeyEvents [v2]

[Martin Fox]

> Updated documentation for various topics related to keyboard handling.
> 
> This documentation deprecates the KP_UP, KP_DOWN, KP_LEFT, and KP_RIGHT key codes. As outlined in JDK-8316307 no platform has ever generated these codes and using them with a Robot will produce inconsistent results.

Martin Fox has updated the pull request incrementally with one additional commit since the last revision:

  Removed deprecataions.

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Changes:
  - all: https://git.openjdk.org/jfx/pull/2036/files
  - new: https://git.openjdk.org/jfx/pull/2036/files/53594042..94b9cc93

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jfx&pr=2036&range=01
 - incr: https://webrevs.openjdk.org/?repo=jfx&pr=2036&range=00-01

  Stats: 12 lines in 1 file changed: 0 ins; 4 del; 8 mod
  Patch: https://git.openjdk.org/jfx/pull/2036.diff
  Fetch: git fetch https://git.openjdk.org/jfx.git pull/2036/head:pull/2036

PR: https://git.openjdk.org/jfx/pull/2036