[feature request] select completion candidates

[xFA25E]

Hi, I thought about adding a support for default Emacs completion. Is it a good idea?

I'm not sure, because this package provides avy jumping only for the current buffer. Instead. for the completion buffer, your point can be in the minibuffer or in an another buffer (when you call completion-at-point). In ace-link command, the code would be required to check for minibuffer-mode, completion-in-region-mode or completion-list-mode.

You can see an example implementation here. I would send a PR.