RFR: hs_err.log files in bug reports

[Jesper Wilhelmsson]

Added a section to inform about sensitive information in hs_err.log files.

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Commit messages:
 - hs_err.log files in bug reports

Changes: https://git.openjdk.org/guide/pull/95/files
 Webrev: https://webrevs.openjdk.org/?repo=guide&pr=95&range=00
  Stats: 8 lines in 2 files changed: 7 ins; 0 del; 1 mod
  Patch: https://git.openjdk.org/guide/pull/95.diff
  Fetch: git fetch https://git.openjdk.org/guide pull/95/head:pull/95

PR: https://git.openjdk.org/guide/pull/95