Document `flow-control` keyword in onion service descriptors
C tor has:
src/feature/hs/hs_descriptor.c:#define str_flow_control "flow-control"
src/feature/hs/hs_descriptor.c: T01(str_flow_control, R3_FLOW_CONTROL, GE(2), NO_OBJ),
But the string flow-control
appears nowhere in rend-spec-v3.
Maybe it's time to merge the key parts of prop 324 into our specs?