Update name of deprecated str::trim_right

Author: dtolnay

tests/test.rs

@@ -617,7 +617,7 @@ where
         // Make sure every prefix is an EOF error, except that a prefix of a
         // number may be a valid number.
         if !json_value.is_number() {
-            for (i, _) in s.trim_right().char_indices() {
+            for (i, _) in s.trim_end().char_indices() {
                 assert!(from_str::<Value>(&s[..i]).unwrap_err().is_eof());
                 assert!(from_str::<IgnoredAny>(&s[..i]).unwrap_err().is_eof());
             }