DOCS: Connect the clock in causal direction

[cstjean]

This is really a question maskerading as a PR, but given that ?connect says:

PLEASE NOTE: The connection is assumed to be causal, meaning that

connect(C.output, :plant_input, P.input)

is correct, whereas

connect(P.input, :plant_input, C.output)

typically is not (unless the model is an inverse model).

I'm assuming that connect(src.input, clk.output) yields the right answer, but as a casual reader trying to figure out what a ContinuousClock is, the causal direction helps understand what's going on.

[baggepinnen]

The change is fine. The comment

The connection is assumed to be causal, meaning that
connect(C.output, :plant_input, P.input)

only applies to connections that create an analysis point. If there is no analysis point created you can have the arguments to the connect statement in any order