Update uitests

Author: cgm616

tests/ui/xor_used_as_pow.stderr

@@ -50,3 +50,17 @@ LL |     let _ = 10 ^ 0;
 
 error: aborting due to 7 previous errors
 
+error: it appears you are trying to get a power of two, but `^` is not an exponentiation operator
+  --> $DIR/xor_used_as_pow.rs:29:17
+   |
+LL |         let _ = 2 ^ x;
+   |                  ^^^^ help: use a bitshift instead: `1_u32 << 15`
+
+error: `^` is not an exponentiation operator but appears to have been used as one
+  --> $DIR/xor_used_as_pow.rs:30:17
+   |
+LL |         let _ = 10 ^ x;
+   |                  ^^^^^
+   |
+   = help: did you mean to use .pow()?
+