fix(book): fix typo, array pop, and BST images

Typos in book content: makePizza parameter, array.pop() mutation, and BST node values

Fixes: amejiarosario#38

Author: mdribera

book/content/part01/algorithms-analysis.asc

@@ -33,7 +33,7 @@ Algorithms (as you might know) are steps of how to do some tasks. When you cook,
 ----
 import { punchDown, rollOut, applyToppings, Oven } from '../pizza-utils';
 
-function makePizza(dough, toppins = ['cheese']) {
+function makePizza(dough, toppings = ['cheese']) {
     const oven = new Oven(450);
     const punchedDough = punchDown(dough);
     const rolledDough = rollOut(punchedDough);

book/content/part02/array.asc

@@ -234,7 +234,7 @@ Removing the last element is very straightforward:
 ----
 const array = [2, 5, 1, 9, 111];
 array.pop();  // ↪️111
-// array: [2, 5, 1, 9, 111]
+// array: [2, 5, 1, 9]
 ----
 
 No element other element has been shifted, so it’s an _O(1)_ runtime.