Update runtime files.
diff --git a/runtime/doc/usr_30.txt b/runtime/doc/usr_30.txt
index 7363236..bcb7b59 100644
--- a/runtime/doc/usr_30.txt
+++ b/runtime/doc/usr_30.txt
@@ -336,7 +336,7 @@
==============================================================================
*30.4* Other indenting
-The most simple form of automatic indenting is with the 'autoindent' option.
+The simplest form of automatic indenting is with the 'autoindent' option.
It uses the indent from the previous line. A bit smarter is the 'smartindent'
option. This is useful for languages where no indent file is available.
'smartindent' is not as smart as 'cindent', but smarter than 'autoindent'.