RFR: Misc minor updates

[Jesper Wilhelmsson]

* Updated code owners
* Removed text duplication around the -na labels
* Fixed typos
* Changed the order of fields in the Release Note creation to match the order in JBS and added a note about Component/Subcomponent

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Commit messages:
 - Misc minor updates

Changes: https://git.openjdk.org/guide/pull/132/files
  Webrev: https://webrevs.openjdk.org/?repo=guide&pr=132&range=00
  Stats: 29 lines in 3 files changed: 7 ins; 11 del; 11 mod
  Patch: https://git.openjdk.org/guide/pull/132.diff
  Fetch: git fetch https://git.openjdk.org/guide.git pull/132/head:pull/132

PR: https://git.openjdk.org/guide/pull/132