RFR: 8296953: Fix a typo in exception documentation

[Pavel Rappo]

Please review this trivial documentation change that fixes a typo accidentally found while comparing javadoc output for an unrelated change in jdk.javadoc.

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Commit messages:
 - Initial commit

Changes: https://git.openjdk.org/jdk/pull/11140/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=11140&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8296953
  Stats: 4 lines in 2 files changed: 0 ins; 0 del; 4 mod
  Patch: https://git.openjdk.org/jdk/pull/11140.diff
  Fetch: git fetch https://git.openjdk.org/jdk pull/11140/head:pull/11140

PR: https://git.openjdk.org/jdk/pull/11140