FAST002's rule documentation reads:

The [FastAPI documentation] recommends the use of [`typing.Annotated`] for
<!-- ... -->
[fastAPI documentation]: https://fastapi.tiangolo.com/tutorial/query-params-str-validations/?h=annotated#advantages-of-annotated
[typing.Annotated]: https://docs.python.org/3/library/typing.html#typing.Annotated

This is how PyCharm renders it:

And GitHub:

The FastAPI documentation recommends the use of [typing.Annotated] for

CommonMark dingus is no different:

<p>The <a href="https://fastapi.tiangolo.com/tutorial/query-params-str-validations/?h=annotated#advantages-of-annotated">FastAPI documentation</a> recommends the use of [<code>typing.Annotated</code>] for</p>

Shortcut reference links of the form [`something`] must have a corresponding link reference definition whose label is also backtick-quoted (related: #14348).

For reference, the matching algorithm is defined as:

One label matches another just in case their normalized forms are equal. To normalize a label, strip off the opening and closing brackets, perform the Unicode case fold, strip leading and trailing spaces, tabs, and line endings, and collapse consecutive internal spaces, tabs, and line endings to a single space.

Here's what a fix would look like:

 The [FastAPI documentation] recommends the use of [`typing.Annotated`] for
 <!-- ... -->
 [fastAPI documentation]: https://fastapi.tiangolo.com/tutorial/query-params-str-validations/?h=annotated#advantages-of-annotated
-[typing.Annotated]: https://docs.python.org/3/library/typing.html#typing.Annotated
+[`typing.Annotated`]: https://docs.python.org/3/library/typing.html#typing.Annotated