See where a component is used in an application

Likely very difficult to implement. In the short term, it may be worth adding a tag like:

```
@see foo.html .fooClass
@see bar.html .barClass
```

This could just draw focus to or even highlight something on a page.

No source files, tests, or entry points are named. Start by reviewing how documentation tags are parsed and rendered, then determine how @see references such as foo.html .fooClass should resolve and highlight a component. Done means the syntax is supported and the referenced element can be located or focused in the generated documentation.

Written by the indexing model from the issue text.