title: Add command or environment to AucTeX autocomplete list
body: <p>I use a lot the autocomplete feature for commands and environments of AucTeX, via the <code>TeX-insert-macro</code> and <code>LaTeX-environment</code> functions. But is there a way to add to the built-in list more commands and macros (<code>\enquote{}</code>, <code>\noindent</code>, etc.)?</p>