I got tired of drive-by spelling fixes, so I figured I'd just take care of them all at once.
This only corrects errors in the dartdocs, not regular comments, and I skipped any sample code in the dartdocs. It doesn't touch any identifiers in the dartdocs either. No code changes, just comments.
* alwaysUse24HourFormat in MediaQuery and time picker
* docs; dead code
* address some comments
* MaterialLocalizations.timeOfDayFormat is the single source of 24-hour-formattedness
* Make TimePickerDialog private again
* wire up MediaQueryData.fromWindow to Window