Author: Marcus Green
MDL-58248 theme_boost: label/span for sidepanel expand button
Add string "Side panel" to make the purpose of
trigram/hamburger icon at top left clearer, particularly
when using screen readers e.g. Jaws/NVDA.
Currently it reads out only "expand"
http://git.moodle.org/gw?p=moodle.git;a=commit;h=7dc35ed9d23efd093d7eb71204610ebe72887d81
http://github.com/moodle/moodle/commit/7dc35ed9d23efd093d7eb71204610ebe72887d81
+ 3.3 en [sidepanel,core]