Add missing parenthesis

Author: iveysaur

src/components/slider/slider.ts

@@ -367,7 +367,7 @@ export class SliderRenderer {
     transparent 2px, transparent ${tickSeparation - 1}px)`;
     // Add a tick to the very end by starting on the right side and adding a 2px black line.
     lastTickContainer.style.background = `linear-gradient(to left, #000000, #000000 2px,
-    transparent 2px, transparent`;
+    transparent 2px, transparent)`;
 
     // If the second to last tick is too close (a separation of less than half the normal
     // separation), don't show it by decreasing the width of the tick container element.