Amendments: unindented lines get crossed out in the diff visualization

Description: A strange bevahior occured during the creation of an amendment. If a user wants to cross out a sentence, it could happen that the last word and dot of the sentence before got also crossed out. Sometimes it affects the first two word of the crosssed out sentence. In consequence, the diff-version has a wrong visualization.

Examples could be found on Staging Server in meeting 56 under motions in motion "Testantrag Dif-Darstellung" and "Test ABC".

Reproduction:

1. open a meeting
2. go to motions
3. create a motions with the plus-icon. add two paragraphs with at least 3 sentence per paragraph.
4. create an amendment to the motion. choose the first paragraph and delete the middle sentence.
5. the diff-version is incorrect. the middle sentence is not correctly deleted with a red line.

Expected behavior: The dif-version must be correctly displayed.

Reproduce the issue in a meeting's motions by creating a motion with two paragraphs, amending the first paragraph, and deleting its middle sentence. Compare the normal and diff versions, including the staging examples in meeting 56, and consider the work done when the deleted sentence is shown with the correct red line without adjacent words or punctuation crossed out.