Fix edoc error

src/jsone.erl

@@ -222,7 +222,7 @@
 %% - default: `0' <br />
 %%
 %% `undefined_as_null': <br />
-%% - Encodes atom `undefined` as null value <br />
+%% - Encodes atom `undefined' as null value <br />
 
 -type decode_option() :: {object_format, tuple | proplist | map}
                        | {allow_ctrl_chars, boolean()}