* fix(mobile): report composing state from accessory backspace
The accessory path edits the field itself and then mirrors it, but called
applyLiveInputMirror with two arguments where the signature takes three. The
local option type declared it 2-ary, so the type checker never saw the drop.
An omitted composing flag is not "not composing": it selects the Android-only
heuristic that holds the trailing non-ASCII run. A pinyin preedit is plain
ASCII, so the heuristic reads it as committed text and sends it. Typing
`ni hao`, tapping accessory Backspace, then picking a candidate put `ni ha` on
the PTY before the commit, giving `ni ha你好`.
Korean survived this by accident - the non-ASCII heuristic re-derives the
correct hold for Hangul - which is why it went unnoticed.
The held range is the fact the mirror needs, and it is already in scope.
Refs #13345
* fix(mobile): preserve accessory IME report provenance
Neil
a724aa7b08