patch 8.2.3555: ModeChanged is not triggered on every mode change

Problem:    ModeChanged is not triggered on every mode change.
Solution:   Also trigger on minor mode changes. (Maguns Gross, closes #8999)
diff --git a/src/terminal.c b/src/terminal.c
index e9dd8ea..bb3035b 100644
--- a/src/terminal.c
+++ b/src/terminal.c
@@ -1995,6 +1995,7 @@
 set_terminal_mode(term_T *term, int normal_mode)
 {
     term->tl_normal_mode = normal_mode;
+    trigger_modechanged();
     if (!normal_mode)
 	handle_postponed_scrollback(term);
     VIM_CLEAR(term->tl_status_text);