RFR: JDK-8309416: Misstatement in semantics of methods in javax.lang.model.ElementFilter

[Joe Darcy]

Correct typo in API and make related improvements.

CSR to review: https://bugs.openjdk.org/browse/JDK-8309417

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Commit messages:
 - JDK-8309417: Misstatement in semantics of methods in javax.lang.model.ElementFilter

Changes: https://git.openjdk.org/jdk/pull/14306/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=14306&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8309416
  Stats: 5 lines in 1 file changed: 0 ins; 0 del; 5 mod
  Patch: https://git.openjdk.org/jdk/pull/14306.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/14306/head:pull/14306

PR: https://git.openjdk.org/jdk/pull/14306