Unclear how to set deadline command in deadline parallel command group

[UserC2]

Is your feature request related to a problem? Please describe.
There doesn't appear to be a way to set which command is the "deadline" in a deadline parallel command group. In #160, it was mentioned that the first command in a deadline group is the "deadline" command, but this isn't mentioned in the documentation.

Describe the solution you'd like
Specify that the first command in a deadline group is the deadline command somewhere in the documentation for PathPlanner.