Fixed html_note() where cw_text is XSTYPE_NULL.

html.c

@@ -276,7 +276,7 @@ xs_html *html_note(snac *user, char *summary,
                             xs_html_attr("type", "text"),
                             xs_html_attr("name", "summary"),
                             xs_html_attr("placeholder", L("Sensitive content description")),
-                            xs_html_attr("value", cw_text))))));
+                            xs_html_attr("value", xs_is_null(cw_text) ? "" : cw_text))))));
 
     if (actor_id)
         xs_html_add(form,