Tweak more warnings.

Much like the previous commit.

I think the removal of "the token" in each message is fine here. There
are many more error messages that mention tokens without saying "the
token" than those that do say it.

tests/ui/array-slice-vec/vec-macro-with-comma-only.rs

@@ -1,3 +1,3 @@
 pub fn main() {
-    vec![,]; //~ ERROR no rules expected the token `,`
+    vec![,]; //~ ERROR no rules expected `,`
 }