I find this really useful, but it's very difficult to find information on it anywhere.
Example of type-based search: https://users.rust-lang.org/t/a-year-in-rust-and-i-still-cant-read-the-docs/46872/20
This would be a good first issue. The documentation should go somewhere in https://github.com/rust-lang/rust/tree/master/src/doc/rustdoc/src.
@rustbot claim
I'll look into any other obscure search features like this, and be sure to document them. (I'll be sure to document at least this one)

@jyn514 I've actually found that this feature is documented in the "Search Tricks" section of the help dialog.
And I don't find that it would really be helpful to document this in the rustdoc book as it's more of an emitted feature rather than a rustdoc feature itself. If it wasn't added to the search tricks already, I would add it there.
@rustbot release-assignment
I feel that the help dialog is already easy to find enough, though the for more options... might be disambiguated to for help... or something like that.

Hmm that does seem simple enough but I never found it after a year in rust ... cc @rust-lang/rustdoc, does anyone have ideas how to make this more discoverable?
It's true that it's hard to find it, maybe we should add a ? button that would also show the popup alongside the search input?
That makes sense, as the settings and theme dropdown are triggered by buttons rather than keyboard shortcuts.
Ok, I'll send a PR tomorrow to add the button then.
Closing since https://github.com/rust-lang/rust/pull/75366 is merged, hopefully that will make this easier to find.
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Ok, I'll send a PR tomorrow to add the button then.