RFR: Cleaning up

[Jesper Wilhelmsson]

Mainly cleaning up JBS labels and fields to use the CSS style for these. Some other minor cleanups and clarifications.

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Commit messages:
 - Cleaning up

Changes: https://git.openjdk.java.net/guide/pull/77/files
 Webrev: https://webrevs.openjdk.java.net/?repo=guide&pr=77&range=00
  Stats: 186 lines in 2 files changed: 4 ins; 12 del; 170 mod
  Patch: https://git.openjdk.java.net/guide/pull/77.diff
  Fetch: git fetch https://git.openjdk.java.net/guide pull/77/head:pull/77

PR: https://git.openjdk.java.net/guide/pull/77