patch 8.1.2044: no easy way to process postponed work

Problem:    No easy way to process postponed work. (Paul Jolly)
Solution:   Add the SafeState autocommand event.
diff --git a/src/ex_getln.c b/src/ex_getln.c
index 5e32f2b..4c88bc8 100644
--- a/src/ex_getln.c
+++ b/src/ex_getln.c
@@ -971,6 +971,9 @@
 				   that occurs while typing a command should
 				   cause the command not to be executed. */
 
+	// Trigger SafeState if nothing is pending.
+	may_trigger_safestate(xpc.xp_numfiles <= 0);
+
 	cursorcmd();		/* set the cursor on the right spot */
 
 	/* Get a character.  Ignore K_IGNORE and K_NOP, they should not do