refactor!: drop chime-play-sound, use chime-sound-file = nil to disable

`chime-play-sound' was redundant with `chime-sound-file' — both had to be
truthy for sound to play, and `chime-sound-file' already documented "set
to nil to disable sound completely".  Two knobs for one decision is a
trap.

I removed the defcustom and the `(when chime-play-sound ...)' guard in
`chime--notify' (it now just checks `chime-sound-file').  Tests, README
quick-start, and the troubleshooting checklist all reference the new
single-knob form.  One redundant test (sound-disabled-via-the-toggle)
got dropped because it now duplicates the sound-file-nil case.

Breaking change: users with `(setq chime-play-sound nil)' in their
config will get a void-variable warning at customize time and lose
their disable.  Migration: `(setq chime-sound-file nil)'.

0 files changed, 0 insertions, 0 deletions