resolve: Support imports of associated types and glob imports from traits

compiler/rustc_error_codes/src/error_codes/E0253.md

@@ -1,9 +1,13 @@
+#### Note: this error code is no longer emitted by the compiler.
+
 Attempt was made to import an unimportable type. This can happen when trying
 to import a type from a trait.
 
 Erroneous code example:
 
-```compile_fail,E0253
+```
+#![feature(import_trait_associated_functions)]
+
 mod foo {
     pub trait MyTrait {
         type SomeType;