Replace proselint with vale

[chenxsan]

Proselint hasn't been updated for more than two years now. I did some research and found there's alternative to use, e.g., vale . vale is used by github, homebrew, etc. as per https://docs.errata.ai/vale/about#open-source-configurations, and it performs much better than proselint with a proselint compatible style https://github.com/errata-ai/proselint.

Therefore I think we can migrate proselint to vale.