D24461: Fix coding style issues in Scene::paintSimpleScreen

zzag added inline comments.

INLINE COMMENTS

> fredrik wrote in scene.cpp:258
> The comment here is lost.

Oops, fixed.

> fredrik wrote in scene.cpp:276
> Why the change to qobject_cast<>?

qobject_cast is considered to be a better choice because it's faster (I didn't benchmark it though) and doesn't need RTTI. However, in this case it is a leftover. Fixed.

REPOSITORY
  R108 KWin

REVISION DETAIL
  https://phabricator.kde.org/D24461

To: zzag, #kwin
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