Update runtime files
diff --git a/runtime/doc/quickref.txt b/runtime/doc/quickref.txt
index 168e785..f6505e6 100644
--- a/runtime/doc/quickref.txt
+++ b/runtime/doc/quickref.txt
@@ -1,4 +1,4 @@
-*quickref.txt* For Vim version 8.1. Last change: 2019 May 31
+*quickref.txt* For Vim version 8.1. Last change: 2019 Jul 18
VIM REFERENCE MANUAL by Bram Moolenaar
@@ -829,6 +829,7 @@
'perldll' name of the Perl dynamic library
'preserveindent' 'pi' preserve the indent structure when reindenting
'previewheight' 'pvh' height of the preview window
+'previewpopup' 'pvp' use popup window for preview
'previewwindow' 'pvw' identifies the preview window
'printdevice' 'pdev' name of the printer to be used for :hardcopy
'printencoding' 'penc' encoding to be used for printing