Add deprecated docblock tags for do_hash() and read_file()
diff --git a/system/helpers/security_helper.php b/system/helpers/security_helper.php
index 7fcb184..7968f9e 100644
--- a/system/helpers/security_helper.php
+++ b/system/helpers/security_helper.php
@@ -80,6 +80,7 @@
 	 * This function is DEPRECATED and should be removed in
 	 * CodeIgniter 3.1+. Use hash() instead.
 	 *
+	 * @deprecated
 	 * @param	string
 	 * @param	string
 	 * @return	string