Add support for /command@bot bot command syntax

mautrix_telegram/bot.py

@@ -127,9 +127,9 @@ class Bot(AbstractUser):
 
         text = message.message
         portal = po.Portal.get_by_entity(message.to_id)
-        if text == "/portal":
+        if text == "/portal" or text == f"/portal@{self.username}":
             await self.handle_command_portal(portal, reply)
-        elif text.startswith("/invite"):
+        elif text.startswith("/invite") or text.startswith(f"/invite@{self.username}"):
             await self.handle_command_invite(portal, reply, mxid=text[len("/invite "):])
 
     async def update(self, update):

mautrix_telegram/formatter/from_matrix.py

@@ -210,7 +210,7 @@ class MatrixParser(HTMLParser):
             self.entities.append(entity)
 
 
-command_regex = re.compile("(\s|^)!([A-Za-z0-9]+)")
+command_regex = re.compile("(\s|^)!([A-Za-z0-9@]+)")
 
 
 def matrix_text_to_telegram(text):