[patch] Error messages of RequiredIfOtherField* validators are not userfriendly

[Steven Armstrong]

When working with RequiredIfOtherFieldEquals and RequiredIfOtherFieldDoesNotEqual validators the error messages can be quite user unfriendly.

Assuming you have a select-box named 'action' where the currently selected option has a value of 2 and a label of 'Forward Message to' you get error messages like:
This field must be given if action is 2

That sort of let's the user sit there feeling dumb. 2, where does that 2 come from and what does it mean ???

With the attached patch applied you can have error messages like:
This field must be given if action is Forward Message to

The label is passed as a third, optional, argument to the validators constructor.

e.g.:
RequiredIfOtherFieldEquals('action', 2)

becomes:
RequiredIfOtherFieldEquals('action', 2, 'Forward Message to')

This is a backwards compatible change.

[Jacob]

Great addition!

It needs docs (in forms.txt); can you add 'em so I can check this in?

[Steven Armstrong]

Patch with docs. You might want to check the docs and rephrase if necessary. English is not my native tounge.

[Jacob]

Fixed in [4577]

[Jacob]

Grrr... fixing.