Update runtime files
diff --git a/runtime/indent/idlang.vim b/runtime/indent/idlang.vim
index e6a1d73..1519865 100644
--- a/runtime/indent/idlang.vim
+++ b/runtime/indent/idlang.vim
@@ -2,7 +2,7 @@
 " Language:	IDL (ft=idlang)
 " Maintainer:	Aleksandar Jelenak <ajelenak AT yahoo.com> (Invalid email address)
 " 		Doug Kearns <dougkearns@gmail.com>
-" Last change:	2017 Jun 13
+" Last change:	2022 Apr 06
 
 " Only load this indent file when no other was loaded.
 if exists("b:did_indent")
@@ -14,6 +14,8 @@
 
 setlocal indentexpr=GetIdlangIndent(v:lnum)
 
+let b:undo_indent = "setl inde< indk<"
+
 " Only define the function once.
 if exists("*GetIdlangIndent")
    finish