Ignore test_attr_in_doctest clippy lint

    warning: unit tests in doctest are not executed
      --> src/lib.rs:34:5
       |
    34 |   //! #[test]
       |  _____^
    35 | | //! fn ui() {
       | |_________^
       |
       = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#test_attr_in_doctest
       = note: `-W clippy::test-attr-in-doctest` implied by `-W clippy::all`
       = help: to override `-W clippy::all` add `#[allow(clippy::test_attr_in_doctest)]`

    warning: unit tests in doctest are not executed
      --> src/lib.rs:81:5
       |
    81 |   //! #[test]
       |  _____^
    82 | | //! fn ui() {
       | |_________^
       |
       = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#test_attr_in_doctest

This is correctly used in trybuild.

src/lib.rs

@@ -227,6 +227,7 @@
     clippy::range_plus_one,
     clippy::similar_names,
     clippy::single_match_else,
+    clippy::test_attr_in_doctest,
     clippy::too_many_lines,
     clippy::trivially_copy_pass_by_ref,
     clippy::unused_self,