Vim 8.1 release

Update version number and information.  Fix a couple of tests.
diff --git a/src/proto/window.pro b/src/proto/window.pro
index e53123c..b21b463 100644
--- a/src/proto/window.pro
+++ b/src/proto/window.pro
@@ -27,7 +27,7 @@
 int make_tabpages(int maxcount);
 int valid_tabpage(tabpage_T *tpc);
 int valid_tabpage_win(tabpage_T *tpc);
-void close_tabpage(tabpage_T *tpc);
+void close_tabpage(tabpage_T *tab);
 tabpage_T *find_tabpage(int n);
 int tabpage_index(tabpage_T *ftp);
 void goto_tabpage(int n);