[jfx17u] RFR: 8274854: Mnemonics for menu containing numeric text not working

[Kevin Rushforth]

Clean backport to `jfx17u`.

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Commit messages:
 - 8274854: Mnemonics for menu containing numeric text not working

Changes: https://git.openjdk.java.net/jfx17u/pull/19/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jfx17u&pr=19&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8274854
  Stats: 194 lines in 3 files changed: 162 ins; 22 del; 10 mod
  Patch: https://git.openjdk.java.net/jfx17u/pull/19.diff
  Fetch: git fetch https://git.openjdk.java.net/jfx17u pull/19/head:pull/19

PR: https://git.openjdk.java.net/jfx17u/pull/19