Auto merge of #7355 - Pyther99:common-tools-link, r=camsteffen
Auto merge of #7355 - Pyther99:common-tools-link, r=camsteffen

Fix link in docs

The [docs](https://github.com/rust-lang/rust-clippy/blob/master/doc/common_tools_writing_lints.md) had an incorrect link for "Checking if a type defines a specific method".

changelog: none

aidancully/rust,graydon/rust,graydon/rust,aidancully/rust,graydon/rust,graydon/rust,graydon/rust,aidancully/rust,graydon/rust,aidancully/rust,aidancully/rust,aidancully/rust