no_std support and cargo.toml doc comments

[mspiegel]

On the main branch, the Cargo.toml has a paragraph of comments about the 'std' feature. Are those comments up to date? I was able to compile regex 1.10.5 with default-features = false. It seems to be working.

[BurntSushi]

It's an outdated comment. The crate features are documented in the crate documentation: https://docs.rs/regex/latest/regex/#crate-features

[mspiegel]

Thanks. I opened #1213 with a fix and it enables the integration tests for no_std.