return breaks with or without min/max

[TomBor]

For now, each statsbreaks methods return breaks as an array that start with min and end with max.
Is it always necessary? Adding min/max is not a core part of each algorithm. Each method purpose is to find breaks.
And I think there is legit use cases when we just want breaks without min/max. For example, in Observable Plot, a threshold scale expect breaks without min/max in domain.

Proposal
Add a a boolean minmax option with true as default for backward compatibility.

How

if (minmax) return breaks.slice(1,-1)

[neocarto]

Thanks Thomas. I'll include it in the next version.