patch 8.2.1874: can't do something just before leaving Insert mode

Problem:    Can't do something just before leaving Insert mode.
Solution:   Add the InsertLeavePre autocommand event. (closes #7177)
diff --git a/src/autocmd.c b/src/autocmd.c
index 57b5674..be35845c 100644
--- a/src/autocmd.c
+++ b/src/autocmd.c
@@ -149,6 +149,7 @@
     {"InsertChange",	EVENT_INSERTCHANGE},
     {"InsertEnter",	EVENT_INSERTENTER},
     {"InsertLeave",	EVENT_INSERTLEAVE},
+    {"InsertLeavePre",	EVENT_INSERTLEAVEPRE},
     {"InsertCharPre",	EVENT_INSERTCHARPRE},
     {"MenuPopup",	EVENT_MENUPOPUP},
     {"OptionSet",	EVENT_OPTIONSET},