rustdoc: include item type in search results

[jsha]

There are a fair number of items that have the same name but different types. For instance, std::panic (the macro) and std::panic (the module). Right now we distinguish these with colors. But that's not accessible for colorblind people. Also some of the colors are not often seen in a context where someone is likely to learn what they mean - for instance green for macros.

We should additionally distinguish search results by writing the actually type of the item. This should probably be its own column, between the item name and the description.

[GuillaumeGomez]

Why not putting it before the name every time instead of putting it in its own column?

[jsha]

For *most* searches, the name is the most important thing and is sufficiently distinctive. So it should be given the most important place, at the beginning of the line. For a small number of searches the type is needed to disambiguate, so it should come later.

[GuillaumeGomez]

Then name (type)?

[jaskij]

Maybe just the first letter even? Stylized differently, or as an icon, so that it stands out more.

Edit to add: My point is, to have the type stand out visually as not a part of the result name and path. Different color, different font, something.

[fmease]

For prior art, take a look at the doc pages of Scala 2 and 3. They use circles containing the initial letter of the item type.

• Scala 2: https://www.scala-lang.org/api/2.13.7/scala/concurrent/index.html?search=string
• Scala 3: https://dotty.epfl.ch/api/scala/math.html
  Click on the magnifier in the top right corner and search for string.
  It used to be the case that they prepended a circle to every single search result but nowadays the apparently
  group by type (maybe they considered it to be too noisy?).
  Just FYI, I am not a big fan of Scala 3's docs in general, I think its UX is horrible in a lot of cases.

[fmease]

Fixed by #110688.