Correction: Rust's help and documentation is HTML-based, and getting a local, automatically updated copy is trivial.
> even "local" docs launch in a web browser
Uh, so what? Can you name a better format for programming language documentation that's also ubiquitously supported?
Maybe you mean Rust's documentation is rendered to HTML. In which case, sure, but so what? Good docs can be rendered to non-HTML formats too, typically for IDEs to display quickly without needing to load a full browser.
It's one of the features I miss most as I code Rust, and the lack is very detrimental to the coding experience, as pulling up a browser is a massive context switch.
Info format. It's supported by Emacs, and Emacs is the most ubiquitous of IDE's.
Sorry, have you been in a coma for 30 years?
I said "ubiquitously supported". There are several orders of magnitude difference between info format support and HTML support.
> Emacs is the most ubiquitous of IDE's
That's laughably wrong.