Update execpy.py: support syntax highlight of discord

execpy.py

@@ -51,7 +51,7 @@ async def execution(self, message):
         if len(lines) <= 1:
             lines.append("")
 
-        if lines[0].startswith("py") and lines[1] == "```":
+        if lines[0].startswith("py") and lines[1] in ["```", "```py", "```python"]:
             commands = lines[0].split()
             wakeword = commands.pop(0)
             if not wakeword in ["py", "python"]: