Remove IncrementalInserter and move it's code to InputModes::Insert
cpp.kak: replace filters with hooks
remove filters, use hooks instead
simplify clang-enable-autocomplete, no need for shell
Allow to ommit the catch part in the try command
regex option highlighter use runtime window rather than creation time one
Tweak insert completion behaviour
Use InsertChar hook for char insertion, and InsertKey for key press