[BUGFIX] Typing after abbr or acronym tag is difficult

Solution: After inserting the abbreviation, position the cursor
after and outside the inserted tag.

Resolves: #47806
Releases: 6.0, 6.1, 6.2
Change-Id: I4e8c47cf031fe3df2772ed47cb42122b8db9a646
Reviewed-on: https://review.typo3.org/23073
Reviewed-by: Stanislas Rolland
Tested-by: Stanislas Rolland