* Remove references to `koSwitchLanguageForAllApplications` and
`koAutoSwitchOSKPages` options, translated strings for them, and
related `GlobalKeyboardChangeManager` -- no longer required since
Win8.
* Remove Windows Vista-, 7-, and 8-specific code paths - except for the
one user-facing setting for installing keyboards on downlevel
operating systems.
* Remove commented code
Fixes: #16433
Test-bot: skip
0f281a6a9d