Add !exec alias to clarify command behavior (#3392)

* add exec as an alias for eval

* add whitespace

Author: DragonSenseiGuy

bot/exts/utils/snekbox/_cog.py

@@ -571,7 +571,7 @@ async def run_job(
 
     @command(
         name="eval",
-        aliases=("e",),
+        aliases=("e", "exec"),
         usage="[python_version] <code, ...>",
         help=f"""
             Run Python code and get the results.