Fix typo in QTextDocument::contentsChange() arguments

Change-Id: I2a9a130e77d87041a6551fea1056f3480d45e548
Reviewed-by: Konstantin Ritt <ritt.ks@gmail.com>
don't install non-framework headers in addition to frameworks, take 2

the redundancy is entirely unnecessary at this point.
the cmake problem that prompted the revert has been fixed long since by
commit 4f5f9331d9fd983e2960501847e0a10dfb0219ff.

This reverts commit 215f137e29ad9176fa1a5d4c446115379f5dbc0d,
thus restoring 6d61dfdbb74a2055438b999c6962f89cc3388eea..

Change-Id: I94749dc18d924163e9c9add500078d88ccd00ffc
Reviewed-by: Stephen Kelly <stephen.kelly@kdab.com>