Update runtime files
diff --git a/runtime/doc/windows.txt b/runtime/doc/windows.txt
index 2b01fb3..0f04b56 100644
--- a/runtime/doc/windows.txt
+++ b/runtime/doc/windows.txt
@@ -137,6 +137,12 @@
status line is inverted anyway; you will only see this problem on terminals
that have termcap codes for italics.
+ *filler-lines*
+The lines after the last buffer line in a window are called filler lines.
+These lines start with a tilde (~) character. By default, these are
+highlighted as NonText (|hl-NonText|). The EndOfBuffer highlight group
+(|hl-EndOfBuffer|) can be used to change the highlighting of filler lines.
+
==============================================================================
3. Opening and closing a window *opening-window* *E36*