When in raw mode, go to level 2, but use level 1 for cooked
so that we don't obfuscate ctrl-c.
A consequnce of this is that CTRL-C is now reported to the app
as CTRL-lowercase-c where we previously reported as CTRL-uppercase-C.
Made a note of the breaking nature of this change in a new changelog
file.
Fixed recognizing SHIFT-TAB
refs: https://github.com/wez/wezterm/issues/2511
