RFR: 7903779: unify logger messages to show position whenever possible

[Athijegannathan Sundararajan]

* logger.warn/.err/.info Position accepting overloads.
* Error message format is: <position>:"fatal"|"error"|"warning"|"info"|:<message> (consistent with clang).
* ClangException has position, severity and spelling. ClangExceptions are printed using logger.print.

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Commit messages:
 - 7903779: unify logger messages to show position whenever possible

Changes: https://git.openjdk.org/jextract/pull/254/files
  Webrev: https://webrevs.openjdk.org/?repo=jextract&pr=254&range=00
  Issue: https://bugs.openjdk.org/browse/CODETOOLS-7903779
  Stats: 95 lines in 10 files changed: 65 ins; 3 del; 27 mod
  Patch: https://git.openjdk.org/jextract/pull/254.diff
  Fetch: git fetch https://git.openjdk.org/jextract.git pull/254/head:pull/254

PR: https://git.openjdk.org/jextract/pull/254