patch 8.1.2219: no autocommand for open window with terminal

Problem:    No autocommand for open window with terminal.
Solution:   Add TerminalWinOpen. (Christian Brabandt)
diff --git a/src/autocmd.c b/src/autocmd.c
index 3f87e93..6ed2971 100644
--- a/src/autocmd.c
+++ b/src/autocmd.c
@@ -174,6 +174,7 @@
     {"TabLeave",	EVENT_TABLEAVE},
     {"TermChanged",	EVENT_TERMCHANGED},
     {"TerminalOpen",	EVENT_TERMINALOPEN},
+    {"TerminalWinOpen", EVENT_TERMINALWINOPEN},
     {"TermResponse",	EVENT_TERMRESPONSE},
     {"TextChanged",	EVENT_TEXTCHANGED},
     {"TextChangedI",	EVENT_TEXTCHANGEDI},