Normalize capitalization in readme

[alerque]

Closes #1694
Closes #1696

[glacambre]

Thanks! I strongly suspect these issues are AI-generated and wouldn't have bothered fixing them :)

[alerque]

I wondered, but most of the AI LLM generated activity I've seen tends to be overly wordy, not low effort like these were. And then there was the one about relying on the system Neovim instance or not which didn't fit with any LLM generated motive I could think of. I decided it was just somebody poking around and nit-picking without really making much effort to understand or contribute. In any case with a side-job typesetting books, the capitalization nitpicks were something I could identify with ;-)