documentation for the macro "set_tuple_transition"

Sets the product transition of one tuple specified by:
1. base policy source type
2. factor policy source type
3. base policy target type
4. factor policy target type
5. class of the transition

It is defined in the file sets.m4.

m4 code:

define(`set_tuple_transition',
`define(`transitionsX$1X$2X$3X$4X$5',
transitionsX$1X$3X$5`'X`'transitionsX$2X$4X$5)')