docs: Fixed three typo in phpdoc and comments (#2994)

Author: Sdfendor

app/code/core/Mage/Checkout/Block/Cart/Item/Renderer.php

@@ -196,7 +196,7 @@ public function getProductOptions()
     }
 
     /**
-     * Get list of all otions for product
+     * Get list of all options for product
      *
      * @return array
      */

app/code/core/Mage/Checkout/Block/Cart/Item/Renderer/Configurable.php

@@ -100,7 +100,7 @@ public function getProductAttributes()
     }
 
     /**
-     * Get list of all otions for product
+     * Get list of all options for product
      *
      * @return array
      */

app/code/core/Mage/Checkout/Model/Type/Onepage.php

@@ -327,7 +327,7 @@ public function saveBilling($data, $customerAddressId)
 
         if (!$this->getQuote()->isVirtual()) {
             /**
-             * Billing address using otions
+             * Billing address using options
              */
             $usingCase = isset($data['use_for_shipping']) ? (int)$data['use_for_shipping'] : 0;