On Cocoa with macOS 11, use plain style for autocompletion to fix problems with truncating text and padding. This makes autocompletion look the same on macOS 11 as macOS 10. Bug #2248.
On Windows, fix encoding used for text display with DirectWrite. Bug #2246.
Implement font locale SCI_SETFONTLOCALE. Initially only for DirectWrite on Win32. Bug #2027.
