Fix ALT overriding text input

[tonsa1]

Issue: https://github.com/EpicGames/raddebugger/issues/16

Set is_editing to true when an active panel begins an edit. If the panel focus goes somewhere else and the edit is still live in the background it should let you use ALT normally. This doesn't take commands into account so they need to be checked seperately.

One other check that I noticed was ws->autocomp_last_frame_idx+1 >= df_frame_index() but this would only work for name types, like expressions where you have the auto complete available. The check in the commit should work for all input types that are build in DF_VIEW_UI_FUNCTION_DEF.

[tonsa1]

If this approach not something you prefer I can edit it if you could share some quick feedback on this @ryanfleury. I can also close this if you would prefer to do it yourself.

[ryanfleury]

This issue was being caused by the debugger not properly interpreting AltGr-based input events correctly, and being too permissive in menu bar hotkey shortcuts, so the correct fix was a bit different.