warn when directories found that hold shell completions.

This will warn then paths for certain shells that have completions are found and tell the user to add a subpackage for it.

In a future date we also want to warn the user to move certain directories where packages have completions to those directories so our default_ functions can move them without problems

@ncopa This is good to merge as-is (assuming there are no mistakes) and in a future date i will add warnings for directories that hold shell completions but are not the right place to put them in, like /etc/bash_completions.d