'loop' vs 'loop=device' in _mount

["Benjamin R. Haskell" <zsh@benizi.com>]

When using completion for mount options, I often run into the annoyance 
that the 'loop' option prompts for the loopback devide to use.  Really, 
though, one needn't specify any device in particular...  Says the man-page 
for 'mount':

'''
If no explicit loop device is mentioned (but just an option `-o loop' is 
given), then mount will try to find some unused loop device and use that.
'''

I'll likely just patch my own completion script to change:

Completion/Unix/Command/_mount, line 325:
-      'loop[use loopback device]:loopback device:_files'
+      'loop[use loopback device]'

since I couldn't tell how to incorporate an '-o' option that accepts an 
optional argument.  But, I also figured I'd mention it here in case 
someone with better completion-fu could work out a simple patch to correct 
the behavior (which is a bug for certain values of bug).

Best,
Ben