Documentation of libstd is lacking of comments on trait implementations

[ticki]

Currently, a lot of the implementation on types in libstd is unexplained, and the behavior of these are not always obvious.

For example,PartialOrd<char> for char is unexplained. Since the exact behavior can unobvious in this case, it should be properly documented (that it compares the unicode codepoints, based on their value). This is just one of the many undocumented implementations in libstd.

[steveklabnik]

This is because rustdoc currently hides them, even if they're there.

[steveklabnik]

(I don't know when this was changed but it was long ago, I think when @alexcrichton was fixing up rustdoc)

[ticki]

No, they're not hidden. Look at impl Rem<u32> for u32 in https://doc.rust-lang.org/std/primitive.u32.html.

They simply lack of documentation, not hidden.

[bluss]

Docs on impl methods are hidden, doc on impl block is not. Some impls contain docs that need to be moved to the impl block.

[steveklabnik]

Ah.

I would still prefer that they just be shown, personally.

[ticki]

Ah, okay. Though, the docs on impl blocks certainly are missing.

[frewsxcv]

Somewhat related: #23271

[mitaa]

Related: #24838