Rollup merge of #42957 - GuillaumeGomez:add-e0619, r=nikomatsakis

Add E0619 error explanation

r? @eddyb

src/test/compile-fail/E0619.rs

@@ -16,3 +16,4 @@ fn main() {
         _ => {}
     }
 }
+

src/test/compile-fail/E0622.rs

@@ -11,6 +11,6 @@
 #![feature(intrinsics)]
 extern "rust-intrinsic" {
     pub static breakpoint : unsafe extern "rust-intrinsic" fn();
-    //~^ ERROR intrinsic must be a function
+    //~^ ERROR intrinsic must be a function [E0622]
 }
 fn main() { unsafe { breakpoint(); } }