fix title of "quote post" button

This is a PR regarding a recent commit by @codinghorror: https://github.com/discourse/discourse/commit/0d26c819a02aba9ab40dfcf24a120e328242fc17

Currently there are two "quote" buttons, both titled "Blockquote". I believe Jeff's intention was to have the first button titled "Quote whole post" and the other one unchanged. This PR reverts Jeff's changes and does that instead :)