Clarify doc about non-finite numbers for non-lenient JsonReader (#1723)

Author: Marcono1234

gson/src/main/java/com/google/gson/stream/JsonReader.java

@@ -890,7 +890,9 @@ public void nextNull() throws IOException {
    *
    * @throws IllegalStateException if the next token is not a literal value.
    * @throws NumberFormatException if the next literal value cannot be parsed
-   *     as a double, or is non-finite.
+   *     as a double.
+   * @throws MalformedJsonException if the next literal value is NaN or Infinity
+   *     and this reader is not {@link #setLenient(boolean) lenient}.
    */
   public double nextDouble() throws IOException {
     int p = peeked;