False Positives for Determinant

## Version

MathCAT 0.7.5

## Issue

MathCAT seems to assume that vertical bars surrounding a capital letter implies that the determinant of a matrix is being taken, as in $|J|$, although it seems that "absolute value" would be a safer inference. When working with matrices and scalars that happen to be labeled by capital letters, MathCAT's output can be very misleading, as one may assume that $\det J$ was explicitly written.