fix: Separate typed instance for each PocomathInstance (#15)

Also starts each PocomathInstance with no types at all, and uses the new
  situation to eliminate the need for a Complex "base case".

  Resolves #14.
  Resolves #13.

Co-authored-by: Glen Whitney <glen@studioinfinity.org>
Reviewed-on: #15

src/number/negate.mjs

@@ -0,0 +1,3 @@
+export { Types } from './Types/number.mjs'
+
+export const negate = {number: [[], n => -n]}