"override" mention and tme_url on Me

That's not **really** an override, but by adding an inherent methods
we "hide" methods from `Deref<Target = User>`, that allows us to return
non-option types from `me.mention()` and `me.tme_url()` -- bots must
always have usernames.

CHANGELOG.md

@@ -12,6 +12,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - `UserId::{url, is_anonymous, is_channel, is_telegram}` convenience functions ([#197][pr197]) 
 - `User::{tme_url, preferably_tme_url}` convenience functions ([#197][pr197])
 - `Me::username` and `Deref<Target = User>` implementation for `Me` ([#197][pr197])
+- `Me::{mention, tme_url}` ([#197][pr197])
 
 [pr197]: https://github.com/teloxide/teloxide-core/pull/197
 

src/types/me.rs

@@ -32,6 +32,16 @@ impl Me {
             .as_deref()
             .expect("Bots must have usernames")
     }
+
+    /// Returns a username mention of this bot.
+    pub fn mention(&self) -> String {
+        format!("@{}", self.username())
+    }
+
+    /// Returns an URL that links to this bot in the form of `t.me/<...>`.
+    pub fn tme_url(&self) -> reqwest::Url {
+        format!("https://t.me/{}", self.username()).parse().unwrap()
+    }
 }
 
 impl Deref for Me {