Correct English in default validation messages

[thomasfw]

Some of the default validation error messages could do with some changes so that they read a bit better.

For example, the same: rule error message is "The :attribute must be same with :field", and should instead read "The :attribute must be same as :field".

I'd also like to suggest removing the leading "The" from all default messages. In a lot of scenarios it doesn't read well, and omitting it makes more sense.

(I'll submit a PR to fix both of these if you're receptive to the changes).