Only look for `tidy` when running rustdoc tests
Only look for `tidy` when running rustdoc tests

This avoids printing lots of unnecessary errors, as well as making the
test suite slightly faster.

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