add syntax for a map that models a property

[williamdemeo]

Description

Addresses one item of #282

In particular, instead of renaming filter^m, we add syntax so that filter^m sp m can be denoted by m \vDash sp.

Checklist

• Commit sequence broadly makes sense and commits have useful messages
• Code is formatted according to CONTRIBUTING.md
• Self-reviewed the diff

[WhatisRT]

I think this notation is more confusing than just writing filterᵐ. We need to have less uncommon notations, not more.