twitter/bootstrap — pull request #8068 by lipis-zeta (2013-06-03 23:19:01+00:00)
Title: Changed the color of the .help-block n the .form-field-validation() mixin

When a form `has-error` (or something) I think it's a good idea to also change the color of the `.help-block` to the relevant color to emphasize what has to be done there.