Fix E0229 unit tests

Author: Matthias Rabault

src/test/compile-fail/E0229.rs

@@ -20,7 +20,9 @@ impl Foo for isize {
     fn boo(&self) -> usize { 42 }
 }
 
-fn baz<I>(x: &<I as Foo<A=Bar>>::A) {} //~ ERROR E0229
+fn baz<I>(x: &<I as Foo<A=Bar>>::A) {}
+//~^ ERROR associated type bindings are not allowed here [E0229]
+//~| NOTE associate type not allowed here
 
 fn main() {
 }

src/test/compile-fail/issue-23543.rs

@@ -16,6 +16,7 @@ pub trait D {
     fn f<T>(self)
         where T<Bogus = Foo>: A;
         //~^ ERROR associated type bindings are not allowed here [E0229]
+        //~| NOTE associate type not allowed here
 }
 
 fn main() {}

src/test/compile-fail/issue-23544.rs

@@ -14,6 +14,7 @@ pub trait D {
     fn f<T>(self)
         where T<Bogus = Self::AlsoBogus>: A;
         //~^ ERROR associated type bindings are not allowed here [E0229]
+        //~| NOTE associate type not allowed here
 }
 
 fn main() {}