#267 Documentation: Mode Transitions should refer to the C Actions

[Stefan Bellon]

While I looked at the "Mode Transitions" in order to find out how to use GOSUB() and GOUP(), I did not find how to use it from within C block code. Perhaps a reference to the "C Actions" (push_mode, pop_mode, etc.) would be nice.

[Frank-Rene Schäfer]

Done in next release.