Correct QSoundEffect::supportedMimeTypes() documentation.

Change-Id: I154b124949ee4f07ea413d8cdb419fcc08cb8324
Reviewed-by: Topi Reiniö <topi.reinio@digia.com>
Merge remote-tracking branch 'origin/stable' into dev

Change-Id: Iefedab3cfc470affbd3118a4e9eb3c892945cd2a
Merge "Merge remote-tracking branch 'origin/stable' into dev" into refs/staging/dev