The keyboard shortcut was already in use.
I therefore renamed custom_functions into custom runs.
That way I can add multiple things in the future.
E.g. the items to select can also be a table which defines the name as
well as what to execute. That way I could add functions, commands and
other things.
Use omni after more specific completions.
Add buffer to completion, not as fallback. I often wanna complete from
current buffer.
Keep syntax consistent when requiring lua modules.
Daniel Siepmann