Don't print anything when a prompt hasn't changed

[pokey]

When I call publish on a prompt, I get a message, even if the prompt hasn't changed.

[jamie-rasmussen]

This behavior is not specific to prompts, other Weave objects are the same.

The object publishing might be happening in a subsequent process execution where a lack of output may make the user think the publish had not been called - I'm not sure there's a behavior here that everyone would be happy with. We have a WEAVE_PRINT_CALL_LINK environment variable and could make something similar for object publishing, or perhaps allow even finer grained control over output. It's something we'll need to think about.

Thanks for the feedback!