Undo/Redo buttons, refactor menu toggles (#793)

* Make Undo & Redo and the menu buttons into actions; add undo/redo buttons

* Create variables for the ToolIcon colors

* Darken the menu buttons when they’re active

* Put the more intensive test in `perform`

* Fix & restyle hint viewer

* Add pinch zoom for macOS Safari

* Chrome/Firefox trackpad pinch zoom

* openedMenu → openMenu

* needsShapeEditor.ts → showSelectedShapeActions.ts

* Call showSelectedShapeActions

src/actions/actionFinalize.tsx

@@ -54,18 +54,13 @@ export const actionFinalize: Action = {
     ((event.key === KEYS.ESCAPE || event.key === KEYS.ENTER) &&
       appState.multiElement !== null),
   PanelComponent: ({ appState, updateData }) => (
-    <div
-      style={{
-        visibility: appState.multiElement != null ? "visible" : "hidden",
-      }}
-    >
-      <ToolButton
-        type="button"
-        icon={done}
-        title={t("buttons.done")}
-        aria-label={t("buttons.done")}
-        onClick={() => updateData(null)}
-      />
-    </div>
+    <ToolButton
+      type="button"
+      icon={done}
+      title={t("buttons.done")}
+      aria-label={t("buttons.done")}
+      onClick={updateData}
+      visible={appState.multiElement != null}
+    />
   ),
 };