FIX: Adds sheet "block" navigation

This was a left over from the old days

Control+right arrow takes you to the next cell with text
or the end of the block

NB: Missing tests

webapp/IronCalc/src/components/Workbook/Workbook.tsx

@@ -249,8 +249,8 @@ const Workbook = (props: { model: Model; workbookState: WorkbookState }) => {
       onToggleUnderline(!value);
     },
     onNavigationToEdge: (direction: NavigationKey): void => {
-      console.log(direction);
-      throw new Error("Function not implemented.");
+      model.onNavigateToEdgeInDirection(direction);
+      setRedrawId((id) => id + 1);
     },
     onPageDown: (): void => {
       model.onPageDown();

webapp/IronCalc/src/components/Workbook/useKeyboardNavigation.ts

@@ -74,7 +74,11 @@ const useKeyboardNavigation = (
       if (event.metaKey || event.ctrlKey) {
         switch (key) {
           case "z": {
-            options.onUndo();
+            if (event.shiftKey) {
+              options.onRedo();
+            } else {
+              options.onUndo();
+            }
             event.stopPropagation();
             event.preventDefault();