Make BotCommands::parse accept bot username as &str

Former-commit-id: 8dfb5268be

src/dispatching/handler_ext.rs

@@ -90,6 +90,6 @@ where
 {
     dptree::entry().chain(dptree::filter_map(move |message: Message, me: Me| {
         let bot_name = me.user.username.expect("Bots must have a username");
-        message.text().and_then(|text| C::parse(text, bot_name).ok())
+        message.text().and_then(|text| C::parse(text, &bot_name).ok())
     }))
 }

src/utils/command.rs

@@ -218,9 +218,7 @@ pub trait BotCommands: Sized {
     ///
     /// `bot_username` is required to parse commands like
     /// `/cmd@username_of_the_bot`.
-    fn parse<N>(s: &str, bot_username: N) -> Result<Self, ParseError>
-    where
-        N: Into<String>;
+    fn parse(s: &str, bot_username: &str) -> Result<Self, ParseError>;
 
     /// Returns descriptions of the commands suitable to be shown to the user
     /// (for example when `/help` command is used).