fix: calculation for {force: false, offset: nonZero} (#139)

Undo the pre-applied offset when calculating whether the element is already
visible (and therefore we shouldn't scroll).

Fixes #138

Author: nburlett

src/scrollTo.js

@@ -196,7 +196,7 @@ export const scroller = () => {
                     : container.offsetHeight;
             const containerTop = initialY;
             const containerBottom = containerTop + containerHeight;
-            const elementTop = targetY;
+            const elementTop = targetY - offset;
             const elementBottom = elementTop + element.offsetHeight;
             if (
                 elementTop >= containerTop &&