completion/alias: rename

There is no reason for this to be in the `plugins` directory, it just needs to have a load priority sufficiently high that it runs after any aliases are defined.

Author: gaelicWizard

plugins/available/alias-completion.plugin.bash completion/available/aliases.completion.bash

@@ -1,10 +1,10 @@
 # This is the default profile of Bash-it
 
 # plugins
-plugins alias-completion
 plugins base
 
 # completion
+completion aliases
 completion bash-it
 completion system