patch 9.0.0083: ModeChanged event not triggered when leaving cmdline window

Problem:    ModeChanged event not triggered when leaving the cmdline window.
Solution:   Call may_trigger_modechanged(). (closes #10791)
diff --git a/src/ex_getln.c b/src/ex_getln.c
index 7fbfded..3c984ff 100644
--- a/src/ex_getln.c
+++ b/src/ex_getln.c
@@ -4649,6 +4649,7 @@
 # endif
 
     State = save_State;
+    may_trigger_modechanged();
     setmouse();
 
     return cmdwin_result;