doc_markdown lint triggers erroneously wihtin links

[stouset]

$ cargo clippy -V
clippy 0.0.212 (329923ed 2020-03-04)

When using Markdown to link to methods within the generated documentation, this lint triggers erroneously. For instance:

/// Call [`new`][Foo::new] to instantiate this struct.
struct Foo {
}

In this made-up example, the target of the link is Foo::new per intra-rustdoc links. Adding backticks around it would break the intra-doc linking.

[jpospychala]

If I read intra-rustdoc links correctly, reference link notation ([label][link]) requires a reference definition somewhere else in the document, like:

/// Call [`new`][fnew] to instantiate this struct.
///
/// [fnew]: Foo::new
struct Foo {
}

Then link doesn't trigger doc_markdown lint.

Otherwise a proper link format is inline link ([label](link)):

/// Call [`new`](Foo::new) to instantiate this struct.
struct Foo {
}

[stouset]

The reference definitions are unnecessary for unambiguous names like Foo::new. They are created automatically. Try it!

[stouset]

Oh no... I just reread the PR and it turns out for over a year I've been doing this wrong. Interestingly it still works (or at least it did back when I first used it).