change span label for E0435 (fix #41871)

src/test/compile-fail/E0435.rs

@@ -11,5 +11,5 @@
 fn main () {
     let foo = 42u32;
     let _: [u8; foo]; //~ ERROR E0435
-    //~| NOTE non-constant used with constant
+    //~| NOTE non-constant value
 }

src/test/compile-fail/non-constant-expr-for-vec-repeat.rs

@@ -14,6 +14,6 @@ fn main() {
     fn bar(n: usize) {
         let _x = [0; n];
         //~^ ERROR attempt to use a non-constant value in a constant [E0435]
-        //~| NOTE non-constant used with constant
+        //~| NOTE non-constant value
     }
 }