output wrong data if add/remove strings

[SailorMax]

GitBlame ignore new line shifts in modified file.

Steps:

1. open document modify history has few people, for example: line 1 by user A line 2 by user B line 3 by user C
2. put cursor in end of line 1 and press Enter
3. check owners of lines 1-4

Expected: line 1 by user A line 2 (empty) has no user line 3 by user B line 4 by user C

Actual: line 1 by user A line 2 (empty) by user B line 3 by user C line 4 has no user