I have opened PR #77 on GitHub.
I have a question, for the text Index Pages:, is it okay to do {{ msg('index-pages') }}: [1] as index-pages already exists and is also used somewhere else and this way we can avoid double translation of same thing. But for languages that are written in right to left, is what I am concern about.

[1]: https://github.com/AS1100K/wscontest/blob/2b85ca9dcc4f1f69d7cd34beba140dccd15942eb/templates/contests_edit.html.twig#L44C15-L44C91

Thanks for the PR!

I have a question, for the text Index Pages:, is it okay to do {{ msg('index-pages') }}: [1] as index-pages already exists and is also used somewhere else and this way we can avoid double translation of same thing.

No, it's best to not re-use messages, and in this case they're also not the same because one needs the colon and one doesn't (different languages may use a different character for that purpose, so it needs to be included in the message).