patch 9.1.0059: No event triggered before creating a window

Problem:  No event is triggered before creating a window.
          (Sergey Vlasov)
Solution: Add the WinNewPre event (Sergey Vlasov)

fixes: #10635
closes: #12761

Signed-off-by: Sergey Vlasov <sergey@vlasov.me>
Signed-off-by: Christian Brabandt <cb@256bit.org>
diff --git a/src/autocmd.c b/src/autocmd.c
index 80ce8ca..7e4a1b2 100644
--- a/src/autocmd.c
+++ b/src/autocmd.c
@@ -188,6 +188,7 @@
     {"VimEnter",	EVENT_VIMENTER},
     {"VimLeave",	EVENT_VIMLEAVE},
     {"VimLeavePre",	EVENT_VIMLEAVEPRE},
+    {"WinNewPre",	EVENT_WINNEWPRE},
     {"WinNew",		EVENT_WINNEW},
     {"WinClosed",	EVENT_WINCLOSED},
     {"WinEnter",	EVENT_WINENTER},