Ensure input files are read as UTF-8

[refack]

Fixes #44

[refack]

Left is content of the released tarball
Right is output after this patch

[PeterFeicht]

Sorry for not responding earlier. I meant to check if this is needed elsewhere too, because I think there's more than one place that creates a parser.

[PeterFeicht]

Please also change the occurrences in preprocess_cssless.py, index2ddg.py, test/test_preprocess.py, and test/test_preprocess_cssless.py.

It would also be great if you could add a test to test/test_preprocess.py, but that's not a blocker for me.

[refack]

Please also change the occurrences in...

👍

It would also be great if you could add a test to

I'm out of the flow, so I'm not sure how to write a test for this...

[refack]

I added a second commit that also makes opening the files explicitly as UTF-8

cppreference-doc/commands/preprocess_cssless.py

Line 32 in 3c821db

with open(src_path, 'r', encoding='utf-8') as a_file: