various: condense or remove unnecessary stanzas

[EricFromCanada]

Almost entirely style fixes.

[khipp]

Dropping the requires_rosetta caveats seems to cause audit failures on affected macOS versions:

❯ brew audit --cask --online --strict birdfont --os mojave
==> Downloading and extracting artifacts
==> Downloading https://birdfont.org/download/birdfont-4.17.0-free.dmg
==> Verifying checksum for '079020bb8ae83904a66259a3e46b7686e583708eaac62bb7bdbffcb61f66563c--birdfont-4.17.0-free.dmg'
audit for birdfont: failed
 - Artifacts require Rosetta 2 but this is not indicated by the caveats!
birdfont
  * line 36, col 2: Artifacts require Rosetta 2 but this is not indicated by the caveats!
Error: 1 problem in 1 cask detected.

❯ brew audit --cask --online --strict reaper --os mojave
==> Downloading and extracting artifacts
==> Downloading https://dlcf.reaper.fm/7.x/reaper739_x86_64.dmg
==> Verifying checksum for 'a27d3fa1fa3b8ee1d1104ad626e7109c107ea406fe64a8f2a903469f2656e629--reaper739_x86_64.dmg'
audit for reaper: failed
 - Artifacts require Rosetta 2 but this is not indicated by the caveats!
reaper
  * line 7, col 4: Artifacts require Rosetta 2 but this is not indicated by the caveats!
Error: 1 problem in 1 cask detected.

[EricFromCanada]

Seems like an audit bug, since Intel-only OS versions by definition don't need Rosetta 2. I'll look into it.