doc: Add quotes around PROJECT_BRIEF setting
doc: Add quotes around PROJECT_BRIEF setting

Otherwise spaces are stripped from the description, previously
rendered as "Object-OrientedJavaScript–UserInterface".

Change-Id: Iea4aec43e91be1c5176ba3ba5b4f9f61fc960674

wikimedia/oojs-ui,wikimedia/oojs-ui,wikimedia/oojs-ui,wikimedia/oojs-ui