feat: add number negate and roll up number functions into one module

test/_pocomath.mjs

@@ -7,4 +7,8 @@ describe('The default full pocomath instance "math"', () => {
       assert.strictEqual(math.add(1.5, 2.5, 3.5), 7.5)
       assert.strictEqual(math.add(Infinity), Infinity)
    })
+   it('can negate numbers', () => {
+      assert.strictEqual(math.negate(-1), 1)
+      assert.strictEqual(math.add(10, math.negate(3)), 7)
+   })
 })