runtime(doc): fix inconsistent indent (#14089)

Signed-off-by: zeertzjq <zeertzjq@outlook.com>
Signed-off-by: Christian Brabandt <cb@256bit.org>
diff --git a/runtime/doc/os_vms.txt b/runtime/doc/os_vms.txt
index ff43548..862f31d 100644
--- a/runtime/doc/os_vms.txt
+++ b/runtime/doc/os_vms.txt
@@ -753,7 +753,7 @@
 	$      say "IA64 platform"
 	$      define/nolog VIM RF10:[UTIL.IA64_EXE] ! IA64 executables
 	$ endif
-        $! VIMRUNTIME must be defined in order to find runtime files
+	$! VIMRUNTIME must be defined in order to find runtime files
 	$ define/nolog VIMRUNTIME RF10:[UTIL.VIM73]
 
 A good example for this approach is the [GNU]gnu_tools.com script from