Update runtime files.
diff --git a/runtime/indent/html.vim b/runtime/indent/html.vim
index fdd743e..ec4fac5 100644
--- a/runtime/indent/html.vim
+++ b/runtime/indent/html.vim
@@ -1,7 +1,7 @@
 " Vim indent script for HTML
 " Maintainer:	Bram Moolenaar
 " Original Author: Andy Wokula <anwoku@yahoo.de>
-" Last Change:	2020 Jul 06
+" Last Change:	2020 Dec 11
 " Version:	1.0 "{{{
 " Description:	HTML indent script with cached state for faster indenting on a
 "		range of lines.
@@ -815,7 +815,7 @@
   let idx = match(prevtext, '^\s*\zs<!--')
   if idx >= 0
     " just below comment start, add a shiftwidth
-    return idx + shiftwidth()
+    return indent(prevlnum) + shiftwidth()
   endif
 
   " Some files add 4 spaces just below a TODO line.  It's difficult to detect