RFR: 8328318: Wrong description in X509Extension.getExtensionValue method javadoc

[Ben Perez]

Removed `PrivateKeyUsagePeriod` from method javadoc and added several commonly used extensions

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Commit messages:
 - removed PrivateKeyUsagePeriod from table and added several other commonly used extensions

Changes: https://git.openjdk.org/jdk/pull/18565/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=18565&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8328318
  Stats: 8 lines in 1 file changed: 6 ins; 2 del; 0 mod
  Patch: https://git.openjdk.org/jdk/pull/18565.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/18565/head:pull/18565

PR: https://git.openjdk.org/jdk/pull/18565