fdo#78826 HIG: missing colons and capitalization in cui, filter

* Fix capitalization
* Standardize spacing
* Standardize Help button’s position

Change-Id: Ibc7152acbe460a9564ab6b97a637f38ea5e7144a
Reviewed-on: https://gerrit.libreoffice.org/12075
Reviewed-by: Samuel Mehrbrodt <s.mehrbrodt@gmail.com>
Tested-by: Samuel Mehrbrodt <s.mehrbrodt@gmail.com>