document context variables

[garfieldnate]

I noticed the button in the debugger printing <ts> for the first time today. I believe it stands for "top state". There are a bunch more of these defined next to ts in Soar:

    soarSymbols.ts_context_variable = make_variable("<ts>");
    soarSymbols.to_context_variable = make_variable("<to>");
    soarSymbols.sss_context_variable = make_variable("<sss>");
    soarSymbols.sso_context_variable = make_variable("<sso>");
    soarSymbols.ss_context_variable = make_variable("<ss>");
    soarSymbols.so_context_variable = make_variable("<so>");
    soarSymbols.s_context_variable = make_variable("<s>");
    soarSymbols.o_context_variable = make_variable("<o>");

I don't see anything in the manual about these, nor any mention of "contextual variables". I would like a mention of this in the print section, and would also like the contextual variables listed and clarified somewhere.