bug#23429: 25.0.90; `dired-do-find-regexp' doc string

[Drew Adams]

> > Presumably something like this (?).
> >
> >  Files with names matching the values of `vc-directory-exclusion-list'
> >  or `grep-find-ignored-files' are not searched.
> 
> Do you not mind that `vc-directory-exclusion-list' enumerates directory
> names, and not regular files?

I said "presumably" because I was presuming that the regexp matched file names. 
Adjust the language accordingly, if it is somehow enough to match a directory 
name (?).