input-method: Lead with a verb in request descriptions

Make all the descriptions consistent by starting the description with a
simple verb (set instead of sets, etc.)  Add or rework a few of the
existing descriptions to fit this form.

Signed-off-by: Bryce Harrington <bryce@osg.samsung.com>
Reviewed-by: Yong Bakos <ybakos@humanoriented.com>