bug#11124: 24.0.94; doc of `customize-apropos-*'

[Drew Adams]

> All of the `customize-apropos-*' commands except for 
> `customize-apropos' need to have their doc strings updated.
> The arg is no longer necessarily a REGEXP.  The doc string
> should say the same thing for these commands as it says for
> `customize-apropos' about the PATTERN arg
> (or refer to the `customize-apropos' doc).

I was wrong about that.  But I should have been right ;-) - they should accept a
PATTERN the same as `customize-apropos' does.

So consider this an enhancement request for each of the `customize-apropos-*'
commands to allow a PATTERN (as in `customize-apropos') instead of just a REGEXP
as arg.

Just use `apropos-read-pattern' in their `interactive' specs.

Or be smarter: move the logic of `apropos-read-pattern' out of the `interactive'
spec, and put it in the body of `customize-apropos':

(when (string= (regexp-quote pattern) pattern)
  (setq pattern  (split-string pattern "[ \t]+" 'OMIT-NULLS)))
(apropos-parse-pattern pattern)

(I also fixed bug #11132 here: provide non-nil 3rd arg.)