Please allow filladapt-turn-on-mode-hooks to have modes added

[Reuben Thomas <rrt@sc3d.org>]

For example, I use lua-mode (not part of Emacs, so no reason to list it by 
default), and since Lua uses single-line comments, I like to use it with 
filladapt-mode, but I can't do it by simply ticking lua-mode-hook in the 
list in the customize page for filladapt-turn-on-mode-hooks, because it's 
not there, and I can't add it.

Of course I can use the traditional way of adding filladapt-mode to the mode 
hook, but that's harder.

-- 
http://rrt.sc3d.org/ | partisan, n.  an adherent without sense (Bierce)