Shell sort edge case fix

Author: Sadanand Pai

cypress/e2e/home.cy.ts

@@ -1,4 +1,4 @@
-describe('template spec', () => {
+describe('landing page', () => {
   beforeEach(() => {
     cy.visit('/');
   });

src/apps/sorting-visualizer/sorting-algorithms/shell.ts

@@ -7,6 +7,11 @@ import {
 import { SortAsyncGenerator } from '@/apps/sorting-visualizer/models/types';
 
 export async function* shellSort(array: number[]): SortAsyncGenerator {
+  if (array.length === 1) {
+    yield* sort(0);
+    return;
+  }
+
   let gap = 1;
 
   while (gap * 3 + 1 < array.length) {