Needs better installation instructions

[kurahaupo]

Although this module can be loaded at any point before, during, or after loading other completion functions, it's more efficient (and slightly more reliable) to load it early, before other completions, rather having to amend them afterwards. So ideally it should be before both system-wide and per-user completion definitions.

The appropriate location will vary with the distribution; in particular Debian has some specialized patches that cause additional startup files to be read.

Create INSTALL.debian, INSTALL.rhel, INSTALL.fedora, INSTALL.suse, etc.