The with-input on p:run isn't optional

In p:run, we find:

<p:run
  name? = NCName>
    (p:with-input? & 
     p:run-input* & 
     p:run-option* & 
     p:output*)
</p:run>

This suggests that the p:with-input element is optional. But later it says:

The anonymous input port is not primary, although it is the only p:input port of p:run. Therefore it will not automatically connect to the default readable port (see Connections in XProc 3.0: An XML Pipeline Language); it needs to be connected to its pipeline input explicitly.

So it isn't optional after all. I suggest we remove the ?.

xproc / 3.0-steps

The with-input on p:run isn't optional #569