summarize control options with verbose = TRUE

[simonpcouch]

In this blog post, Mike writes about a costly mistake of not setting save_pred = TRUE and save_workflow = TRUE when resampling models for use when stacking.

One change that Emil proposed is, when verbose = TRUE (which it more often is when resampling longer-running fits), printing out a quick note summarizing important control options first thing that highlights compatibility with functions that could be applied to the tuning results.