RFR: 8311034: Fix typo in javac man page

[Pavel Rappo]

Please review this trivial fix.

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Commit messages:
 - Initial commit

Changes: https://git.openjdk.org/jdk/pull/14694/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=14694&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8311034
  Stats: 2 lines in 1 file changed: 0 ins; 0 del; 2 mod
  Patch: https://git.openjdk.org/jdk/pull/14694.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/14694/head:pull/14694

PR: https://git.openjdk.org/jdk/pull/14694