explain where to find POD on HTML::Form::Input

[fschlich]

in https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=751465, jidanni suggests adding a little helpful language on where to find more info about HTML::Form::Input objects. my suggestion for a patch would be

--- a/lib/WWW/Mechanize.pm
+++ b/lib/WWW/Mechanize.pm
@@ -2251,7 +2251,8 @@

 find_all_inputs() returns an array of all the input controls in the
 current form whose properties match all of the regexes passed in.
-The controls returned are all descended from HTML::Form::Input.
+The controls returned are all descended from HTML::Form::Input
+(see HTML::Form's "Input" section for details).

 If no criteria are passed, all inputs will be returned.

[oalders]

Closed vi #237 Thanks @fschlich!