Given the current values of the options pp.showLetValues and pp.showLetValues.threshold,
determines whether the local let declaration's value should be omitted.
tacticis whether the goal is for a tactic metavariable. In that case, uses the maximum ofpp.showLetValues.tactic.thresholdandpp.showLetValues.thresholdfor the threshold. In tactics, we usually want to see let values. In contrast, for the "expected type" view we usually do not.