RFR: 8243614: Typo in ReentrantLock's Javadoc

[Martin Buchholz]

Add missing semicolon

Martin's first github pr.

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Commit messages:
 - JDK-8243614-typo

Changes: https://git.openjdk.java.net/jdk/pull/1633/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=1633&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8243614
  Stats: 1 line in 1 file changed: 0 ins; 0 del; 1 mod
  Patch: https://git.openjdk.java.net/jdk/pull/1633.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/1633/head:pull/1633

PR: https://git.openjdk.java.net/jdk/pull/1633