docs/builder: touch up markdown, and some minor rephrasing

- add code-fences with code-hints so that the right hightlighting is applied
- replace `*` for `-` in bullet-lists for consistency with other parts of the
  documentation.
- reduced number of "notes", either by combining some, or by changing some
  to regular text.
- removed "line numbers" from some examples, because there's only four lines,
  which should not need really need line numbers.
- reformat some notes to our new format

Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
(cherry picked from commit 16730a2ab6a9e4edea2dd41c78e10b9696073449)
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
Upstream-commit: 733ae82dae2dd5c5593a3c01fc84b89ebdd6caa0
Component: cli

Author: thaJeztah