Fix double escaping

e75284e52803f5e06fdecb407259a03c17e1a57b escapes a few messages too
eagerly but 1fc00749fbad96a846a7823ec7ab98776115122a only fixes one
of such mistakes.

Without this change, the labels of some toolbar buttons (e.g. Italian
'Redirect', Welsh 'Numbered list') display ''' where apostrophes
should be.

Change-Id: I3265631512c5d22ecc3dafb9d56acecc7d50ad1d