Grammarcells: side transformations not working for pasted text

Issue https://github.com/mbeddr/mbeddr.core/issues/1244 was moved. This is actually the standard behavior that can also be observed in base language. Examples:
`if (true) { }` and typing `else {}` vs just pasting `else{}` or inserting the flag `transient` in `int[]| volatile a;` when the cursor is placed at the vertical bar.

Reproduce the `if (true) { }` and `int[]| volatile a;` examples in the base language, comparing typed input with pasted text and cursor placement at the vertical bar. Determine the expected side-transformation behavior and verify that both examples behave consistently after the issue is addressed.

Written by the indexing model from the issue text.