fdo#78826 HIG: missing colons and capitalization in sd

* Title Case for headings and command buttons
* Sentence case for radio buttons, check boxes, etc.

Change-Id: I68342d2f4c66e2253dded31d80783b3629a3d1d6
Reviewed-on: https://gerrit.libreoffice.org/11577
Reviewed-by: Samuel Mehrbrodt <s.mehrbrodt@gmail.com>
Tested-by: Samuel Mehrbrodt <s.mehrbrodt@gmail.com>