remove obsolete funktion

@@ -66,17 +66,6 @@ impl Markdown {
         }
     }
 
-    pub(crate) fn _to_html_string(&self) -> String {
-        use pulldown_cmark::{Parser, Options, html};
-
-        let mut html_out = String::new();
-        let parser = Parser::new_ext(&self.json.content, Options::all());
-
-        html::push_html(&mut html_out, parser);
-        html_out
-    }
-
-
     fn status_error<I: Display>(status :I) -> Error {
         let err_str = format!("Invalid response status: {}", status);
         Error::from(err_str.as_str())