Merge pull request #2859 from vivekdinesh/typo-fix

Typo Fix
diff --git a/system/helpers/file_helper.php b/system/helpers/file_helper.php
index 0587740..40c2901 100644
--- a/system/helpers/file_helper.php
+++ b/system/helpers/file_helper.php
@@ -298,7 +298,7 @@
 					$fileinfo['readable'] = is_readable($file);
 					break;
 				case 'writable':
-					// There are known problems using is_weritable on IIS.  It may not be reliable - consider fileperms()
+					// There are known problems using is_writable on IIS.  It may not be reliable - consider fileperms()
 					$fileinfo['writable'] = is_writable($file);
 					break;
 				case 'executable':