RFR: Extend documentation regarding logging

[Johan Sjölén]

Hi!

Here's some suggested improvements to the logging documentation. It's currently just a draft, but please feel welcome to come with any suggestions.

-------------

Commit messages:
 - Extend documentation regarding logging

Changes: https://git.openjdk.org/guide/pull/91/files
 Webrev: https://webrevs.openjdk.org/?repo=guide&pr=91&range=00
  Stats: 59 lines in 1 file changed: 51 ins; 2 del; 6 mod
  Patch: https://git.openjdk.org/guide/pull/91.diff
  Fetch: git fetch https://git.openjdk.org/guide pull/91/head:pull/91

PR: https://git.openjdk.org/guide/pull/91