Spell checking

[maxonfjvipon]

It would be nice to add spell checking to the blog. Something similar to [thisj(https://github.com/yegor256/blog/blob/master/Rakefile#L185-L233)

[yegor256]

@maxonfjvipon maybe this one: https://github.com/marketplace/actions/github-spellcheck-action I configured it in this repo: https://github.com/cqfn/kaicode.github.io (maybe will help)