text-input: Fix indentation and paragraph whitespace

Replace the tab indentation of the MIT license with appropriate spaces.
Add one missing line break between two description paragraphs.
Adjust two line breaks to keep descriptions under 80 chars / line.

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