That is, `crate_name::Data` has a canonical path of `crate_name::submodule::Data`.

This might sound like a strange design, since it has the duplicate data.
It's done that way because inlining can happen across crates,
which are compiled separately and might not all be present in the docs.

```json
[
  [ "crate_name", ... ],
  [ "crate_name_2", { "q": [[0, "crate_name::submodule"], [5, "core::option"]], ... }]
]
```

In the above example, a canonical path actually comes from a dependency,
and another one comes from an inlined standard library item:
the canonical path isn't even in the index!
The canonical path might also be private.
In either case, it's never shown to the user, and is only used for deduplication.

Associated types, like methods, store them differently.
These types are connected with an entry in `p` (their "parent")
and each one has an optional third tuple element:

    "p": [[5, "Data", 0, 1]]

That's:

- 5: It's a struct
- "Data": Its name
- 0: Its display path, "crate_name"
- 1: Its canonical path, "crate_name::submodule"

In both cases, the canonical path might not be public at all,
or it might be from another crate that isn't in the docs,
so it's never shown to the user, but is used for deduplication.


## Testing the search engine

While the generated UI is tested using `rustdoc-gui` tests, the
primary way the search engine is tested is the `rustdoc-js` and
`rustdoc-js-std` tests. They run in NodeJS.

A `rustdoc-js` test has a `.rs` and `.js` file, with the same name.
The `.rs` file specifies the hypothetical library crate to run
the searches on (make sure you mark anything you need to find as `pub`).
The `.js` file specifies the actual searches.
The `rustdoc-js-std` tests are the same, but don't require an `.rs`
file, since they use the standard library.

The `.js` file is like a module (except the loader takes care of
`exports` for you). It uses these variables:

|      Name      |              Type              | Description
| -------------- | ------------------------------ | -------------------------------------------------------------------------------------------------------------
| `FILTER_CRATE` | `string`                       | Only include results from the given crate. In the GUI, this is the "Results in <kbd>crate</kbd>" drop-down menu.
| `EXPECTED`     | `[ResultsTable]\|ResultsTable` | List of tests to run, specifying what the hypothetical user types into the search box and sees in the tabs