Doc: Language edits

Changed the section title and removed a redundant sentence.

Change-Id: I16ac77e2df61f488f1feda60d043f6ed95af7f6c
Reviewed-by: Topi Reiniö <topi.reinio@digia.com>
Slider: don't clamp to the initial press point

Change-Id: I5115bbab670f534dae44eb19c2208aff21293889
Reviewed-by: Mitch Curtis <mitch.curtis@digia.com>