patch 9.0.0917: the WinScrolled autocommand event is not enough

Problem:    The WinScrolled autocommand event is not enough.
Solution:   Add WinResized and provide information about what changed.
            (closes #11576)
diff --git a/src/proto/autocmd.pro b/src/proto/autocmd.pro
index 713ae24..1f55f2d 100644
--- a/src/proto/autocmd.pro
+++ b/src/proto/autocmd.pro
@@ -16,6 +16,7 @@
 int apply_autocmds_exarg(event_T event, char_u *fname, char_u *fname_io, int force, buf_T *buf, exarg_T *eap);
 int apply_autocmds_retval(event_T event, char_u *fname, char_u *fname_io, int force, buf_T *buf, int *retval);
 int trigger_cursorhold(void);
+int has_winresized(void);
 int has_winscrolled(void);
 int has_cursormoved(void);
 int has_cursormovedI(void);