The built-in commands are all part of the Core library, which you can modify.
To modify the "look at" command, in the bottom left corner of the Editor window, click Filter, then "Show Library Elements". All the built-in commands will now be shown in the tree - the library ones are shown in grey.
In the tree, under Commands, select the "lookat" command. To edit it, you need to copy it into your game file by clicking the "Copy" button at the top right. You'll then be able to edit the command pattern.
Add a semicolon and then "look #object#" to the command pattern, so the whole pattern now looks like this:
look at #object#; x #object#; examine #object#; exam #object#; ex #object#; look #object#