patch 8.2.4391: command line executed when typing Esc in the GUI

Problem:    Command line executed when typing Esc in the GUI.
Solution:   Move saving/restoring KeyTyped to build_stl_str_hl().
            (closes #9783)
diff --git a/src/buffer.c b/src/buffer.c
index b3e2bc3..bb9c773 100644
--- a/src/buffer.c
+++ b/src/buffer.c
@@ -4164,6 +4164,7 @@
     stl_hlrec_T *sp;
     int		save_must_redraw = must_redraw;
     int		save_redr_type = curwin->w_redr_type;
+    int		save_KeyTyped = KeyTyped;
 
     if (stl_items == NULL)
     {
@@ -5060,6 +5061,9 @@
 	curwin->w_redr_type = save_redr_type;
     }
 
+    // A user function may reset KeyTyped, restore it.
+    KeyTyped = save_KeyTyped;
+
     return width;
 }
 #endif // FEAT_STL_OPT