RFR: 8337344: Typo at RasterPrinterJob.isCancelled

[Prasanta Sadhukhan]

RasterPrinterJob.isCancelled cites
`is a print job is ongoing but will be cancelled and the next opportunity`

"and" -> "at" is fixed and more clarification added..

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Commit messages:
 - print cancel typo fix

Changes: https://git.openjdk.org/jdk/pull/20375/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=20375&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8337344
  Stats: 3 lines in 1 file changed: 1 ins; 0 del; 2 mod
  Patch: https://git.openjdk.org/jdk/pull/20375.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/20375/head:pull/20375

PR: https://git.openjdk.org/jdk/pull/20375