Fixed some typos (#12847)

framework/base/Model.php

@@ -534,7 +534,7 @@ class Model extends Component implements IteratorAggregate, ArrayAccess, Arrayab
     }
 
     /**
-     * Returns the errors for all attribute or a single attribute.
+     * Returns the errors for all attributes or a single attribute.
      * @param string $attribute attribute name. Use null to retrieve errors for all attributes.
      * @property array An array of errors for all attributes. Empty array is returned if no error.
      * The result is a two-dimensional array. See [[getErrors()]] for detailed description.
@@ -633,7 +633,7 @@ class Model extends Component implements IteratorAggregate, ArrayAccess, Arrayab
 
     /**
      * Removes errors for all attributes or a single attribute.
-     * @param string $attribute attribute name. Use null to remove errors for all attribute.
+     * @param string $attribute attribute name. Use null to remove errors for all attributes.
      */
     public function clearErrors($attribute = null)
     {

framework/helpers/BaseArrayHelper.php

@@ -206,7 +206,7 @@ class BaseArrayHelper
 
         if (is_object($array)) {
             // this is expected to fail if the property does not exist, or __get() is not implemented
-            // it is not reliably possible to check whether a property is accessable beforehand
+            // it is not reliably possible to check whether a property is accessible beforehand
             return $array->$key;
         } elseif (is_array($array)) {
             return (isset($array[$key]) || array_key_exists($key, $array)) ? $array[$key] : $default;