rustdoc: properly elide cross-crate host effect args

tests/rustdoc/inline_cross/const-effect-param.rs

@@ -0,0 +1,29 @@
+// Regression test for issue #116629.
+// Check that we don't render host effect parameters & arguments.
+
+// aux-crate:const_effect_param=const-effect-param.rs
+// edition: 2021
+#![crate_name = "user"]
+
+// Don't render the host param on `load` and the host arg `host` passed to `Resource`.
+// @has user/fn.load.html
+// @has - '//pre[@class="rust item-decl"]' "pub const fn load<R>() -> i32\
+//     where \
+//         R: Resource"
+pub use const_effect_param::load;
+
+// Don't render the host arg `true` passed to `Resource`.
+// @has user/fn.lock.html
+// @has - '//pre[@class="rust item-decl"]' "pub const fn lock<R>()\
+//     where \
+//         R: Resource"
+pub use const_effect_param::lock;
+
+// Regression test for an issue introduced in PR #116670.
+// Don't hide the const param `host` since it actually isn't the host effect param.
+// @has user/fn.clash.html
+// @has - '//pre[@class="rust item-decl"]' \
+//    "pub const fn clash<T, const host: u64>()\
+//     where \
+//         T: Clash<host>"
+pub use const_effect_param::clash;