bug: With ignore-multiline-regex set, `--write` doesn't work properly

[spetrosi]

When ignore-multiline-regex is set in config, and I run codespell -w, it removes newlines in edited files, which results in files being reformatted to a single line.

$ echo -e "Thsi line contains a typo\nWhile this line is correct" > test.txt
$ cat test.txt 
Thsi line contains a typo
While this line is correct
$ codespell test.txt 
> Thsi line contains a typo
test.txt:1: Thsi ==> This
$ codespell test.txt -w --ignore-multiline-regex="codespell:ignore-begin.*codespell:ignore-end"
FIXED: test.txt
$ cat test.txt 
$ cat test.txt 
This line contains a typoWhile this line is correct