Suggest similarly named assoc items in trait impls

Previously, the compiler didn't suggest similarly named associated items
unlike we do in many situations. This patch adds such diagnostics for
associated functions, types and constants.

compiler/rustc_resolve/src/lib.rs

@@ -202,11 +202,11 @@ enum ResolutionError<'a> {
     /// parameter list.
     NameAlreadyUsedInParameterList(Symbol, Span),
     /// Error E0407: method is not a member of trait.
-    MethodNotMemberOfTrait(Symbol, &'a str),
+    MethodNotMemberOfTrait(Ident, &'a str, Option<Symbol>),
     /// Error E0437: type is not a member of trait.
-    TypeNotMemberOfTrait(Symbol, &'a str),
+    TypeNotMemberOfTrait(Ident, &'a str, Option<Symbol>),
     /// Error E0438: const is not a member of trait.
-    ConstNotMemberOfTrait(Symbol, &'a str),
+    ConstNotMemberOfTrait(Ident, &'a str, Option<Symbol>),
     /// Error E0408: variable `{}` is not bound in all patterns.
     VariableNotBoundInPattern(&'a BindingError),
     /// Error E0409: variable `{}` is bound in inconsistent ways within the same match arm.