Issue #393538 by Liam Morland, valthebald, dmitrig01, David_Rothstein: Document that check_plain() can issue PHP messages on invalid UTF-8 input.
Issue #393538 by Liam Morland, valthebald, dmitrig01, David_Rothstein: Document that check_plain() can issue PHP messages on invalid UTF-8 input.

brainhell/drupalglass,joshkoenig/golden-god-demo,joshkoenig/golden-god-demo,lincgr/Prueba,brainhell/drupalglass,brainhell/drupalglass,joshkoenig/golden-god-demo,brainhell/drupalglass,joshkoenig/golden-god-demo,brainhell/drupalglass,joshkoenig/golden-god-demo,joshkoenig/golden-god-demo,lincgr/Prueba,lincgr/Prueba,lincgr/Prueba,joshkoenig/golden-god-demo