Rollup merge of rust-lang#82040 - GuillaumeGomez:ensure-src-link, r=CraftSpider

Add test to prevent src link regression

Fixes rust-lang#80502.

This PR is simply about adding a test to prevent a regression.

cc `@bugadani` `@CraftSpider`
r? `@camelid`

Author: JohnTitor

src/test/rustdoc/ensure-src-link.rs

@@ -0,0 +1,6 @@
+#![crate_name = "foo"]
+
+// This test ensures that the [src] link is present on traits items.
+
+// @has foo/trait.Iterator.html '//h3[@id="method.zip"]/a[@class="srclink"]' "[src]"
+pub use std::iter::Iterator;