message: update comment on dump to not indicate that ensure_ascii is true by default
diff: @@ -9047,9 +9047,9 @@ class basic_json
  representation.
  @param[in] indent_char The character to use for indentation if @a indent is
  greater than `0`. The default is ` ` (space).
  - @param[in] ensure_ascii If ensure_ascii is true (the default), all non-ASCII
  - characters in the output are escaped with \uXXXX sequences, and the result
  - consists of ASCII characters only.
  + @param[in] ensure_ascii If ensure_ascii is true, all non-ASCII characters
  + in the output are escaped with \uXXXX sequences, and the result consists
  + of ASCII characters only.
  @return string containing the serialization of the JSON value
  