Fix incorrect comment (#9598)

Motivation:

The comment is incorrect and so missleading

Modification:

Correct the comment

Result:

Correct comment in code

codec-http/src/main/java/io/netty/handler/codec/http/QueryStringEncoder.java

@@ -221,7 +221,7 @@ private static char forDigit(int digit) {
      * unreserved characters do not need to be encoded, and include uppercase and lowercase
      * letters, decimal digits, hyphen, period, underscore, and tilde.
      * <p>
-     * unreserved  = ALPHA / DIGIT / "-" / "." / "_" / "~"
+     * unreserved  = ALPHA / DIGIT / "-" / "_" / "." / "*"
      *
      * @param ch the char to be judged whether it need to be encode
      * @return true or false