It's a little odd that the primary usage of this (e.g. `allow(...).to receive_message_chain(...)`) isn't highlighted here, and instead the `expect` form is.  Also, calling `receive_message_chain` a "matcher" is stretching it (even though it implements the rspec-expectations matcher protocol).  I'd probably phrase this something like:

* Add `receive_message_chain` which provides the functionality of the old `stub_chain` for the new allow/expect syntax. Use it like so: `allow(...).to receive_message_chain(:foo, :bar, :bazz)`. (Sam Phippen).