Add docstring to transition

src/equations.jl

@@ -70,6 +70,21 @@ function Base.:(==)(transition1::Transition, transition2::Transition)
     transition1.synchronize == transition2.synchronize &&
     transition1.priority == transition2.priority
 end
+
+"""
+    transition(from, to, cond; immediate::Bool = true, reset::Bool = true, synchronize::Bool = false, priority::Int = 1)
+
+Create a transition from state `from` to state `to` that is enabled when transitioncondition `cond` evaluates to `true`.
+
+# Arguments:
+- `from`: The source state of the transition.
+- `to`: The target state of the transition.
+- `cond`: A transition condition that evaluates to a Bool, such as `ticksInState() >= 2`.
+- `immediate`: If `true`, the transition will fire at the same tick as it becomes true, if `false`, the actions of the state are evaluated first, and the transition fires during the next tick.
+- `reset`: If true, the destination state `to` is reset to its initial condition when the transition fires.
+- `synchronize`: If true, the transition will only fire if all sub-state machines in the source state are in their final (terminal) state. A final state is one that has no outgoing transitions.
+- `priority`: If a state has more than one outgoing transition, all outgoing transitions must have a unique priority. The transitions are evaluated in priority order, i.e., the transition with priority 1 is evaluated first.
+"""
 function transition(from, to, cond;
         immediate::Bool = true, reset::Bool = true, synchronize::Bool = false,
         priority::Int = 1)