Summary

This is a small update to Cell and Grid to ensure capacity is set properly. In Cell, we explicitly force keyword arguments. In Grid, we pass capacity as a keyword argument instead of as an argument. All other discrete spaces already handle this correctly.

Bug / Issue

Closes #3505.

Implementation

• Cell now enforces explicit use of keyword arguments
• Grid passes capacity as a keyword argument.

Testing

An additional test is added to check that capacity is properly set on a cell in a (subclass) of Grid.