patch 8.2.4865: :startinsert right after :stopinsert may not work

Problem:    :startinsert right after :stopinsert does not work when popup menu
            is still visible.
Solution:   Use ins_compl_active() instead of pum_visible(). (closes #10352)
diff --git a/src/edit.c b/src/edit.c
index 61c1694..65b760b 100644
--- a/src/edit.c
+++ b/src/edit.c
@@ -448,7 +448,7 @@
 	if (update_Insstart_orig)
 	    Insstart_orig = Insstart;
 
-	if (stop_insert_mode && !pum_visible())
+	if (stop_insert_mode && !ins_compl_active())
 	{
 	    // ":stopinsert" used or 'insertmode' reset
 	    count = 0;