OverEachLinear​(AngouriMath.​Entity,​AngouriMath.​Entity,​AngouriMath.​Entity,​System.​Int32,​AngouriMath.​Entity.​Variable)

numerator over a denominator as terms each over one linear: the
polynomial part first, divided by the denominator as it is written,
and the proper rest split into partial fractions over overTheLinears,
the same denominator with each quadratic in it written as the linears of its roots.
Divided by those linears, `x^2` over `(x - r)(x + r)`, `r = sqrt(-a/b)`, left a remainder
in `r^2` that nothing read as `-a/b`. Only where the fraction is not proper already:
divided, `x` over `(c + d x)(x - 2)` came back as a quotient and a remainder
`2 provided not c + d x = 0`, which nothing splits. Null where the split declines.