Tab Completion API

[TorchedSammy]

hilbish tab completion is pretty meh right now. it only tab completes files and does it very stupidly (filenames with spaces wont work) so here is a place for anyone to propose ideas for a lua tab completion api to extend and customize completions for hilbish

[TorchedSammy]

decision: hilbish will by itself complete commands, and if a completer isnt made for it then hilbish will just complete files
to make a completer for a command, a complete function will be used. it is in similar use of registering a commander and is expected
to return a table of entries to complete, like:

complete('command.git', function()
   return {
       'add'
       commit = {'-m', '--amend'},
       ...
    } 
end)

nested tables are for how deep you want the completions to be and the special <file> will be used for file completions