I appreciate that it would be useful but I don't know that our team will be finding lots of details on this.
This is the documentation provided by Xenforo for the 1.X forums:
https://xenforo.com/docs/xf1/
I did not find any results related to this topic.
I did do a quick google search and...
I can look and see if Xenforo has a list of anything.
I found a list of hardcoded shrotcuts for the editor like you said (bold and italics and the like) but not one for the actual forum software.
Looks like from this thread there might be more in the 2.x branch of form software we are moving...