Correct return type of methods and typo correction.

Author: Saurabh Parekh

app/code/Magento/CatalogRule/Controller/Adminhtml/Promo/Widget/CategoriesJson.php

@@ -8,6 +8,7 @@
 
 use Magento\Backend\App\Action\Context;
 use Magento\Catalog\Model\Category;
+use Magento\Customer\Model\Attribute\Data\Boolean;
 use Magento\Framework\Registry;
 
 class CategoriesJson extends \Magento\CatalogRule\Controller\Adminhtml\Promo\Widget
@@ -32,7 +33,7 @@ public function __construct(Context $context, Registry $coreRegistry)
     /**
      * Initialize category object in registry
      *
-     * @return Category
+     * @return Category|Boolean
      */
     protected function _initCategory()
     {

app/code/Magento/CatalogSearch/Model/ResourceModel/Engine.php

@@ -120,7 +120,7 @@ public function processAttributeValue($attribute, $value)
      *
      * @param array $index
      * @param string $separator
-     * @return string
+     * @return array
      */
     public function prepareEntityIndex($index, $separator = ' ')
     {

app/code/Magento/UrlRewrite/Service/V1/Data/UrlRewrite.php

@@ -79,7 +79,7 @@ public function getUrlRewriteId()
 
     /**
      * @param int $urlRewriteId
-     * @return int
+     * @return $this
      */
     public function setUrlRewriteId($urlRewriteId)
     {

app/code/Magento/User/Model/Backend/Config/ObserverConfig.php

@@ -72,7 +72,7 @@ public function getAdminPasswordLifetime()
     }
 
     /**
-     * Get admin maxiumum security failures from config
+     * Get admin maximum security failures from config
      *
      * @return int
      */