nex3/haml — pull request #441 by pivotal-casebook (2011-10-13 20:58:47+00:00)
Title: Fix signature of InstanceTag#content_tag. 

This is from [this pull request](https://github.com/nex3/haml/pull/431), fixed up and switched to `stable` branch per nex3's request.

`InstanceTag#content_tag` should take a block to match the signature of `ActionView::Helpers::TagHelper`.

This makes it possible to use `FormBuilder#label` with a block in Haml.

This method had no test coverage and we weren't confident adding in tests.