Tab completions

[fenhl]

The commands (including shell functions and aliases) included here should have tab completion support. Need to figure out how to write these.

Resources:

• https://mads-hartmann.com/2017/08/06/writing-zsh-completion-scripts.html
• https://github.com/zsh-users/zsh-completions/blob/master/zsh-completions-howto.org

[fenhl]

Quick survey of the current commands Zsh knows about on bureflux (via whence -Smv '*'):

• 73 aliases
• 31 reserved words
• 1338 shell functions starting with _ (including 1054 autoload shell functions)
• 97 shell functions not starting with _ (including 5 autoload shell functions)
• 102 shell builtins
• 2888 regular commands

The shell functions starting with _ are probably completions and their helpers. For everything else, I need a way to check if there's completion.