py: Shorten a couple of error messages.

py/compile.c

@@ -1524,7 +1524,7 @@ STATIC void compile_try_except(compiler_t *comp, mp_parse_node_t pn_body, int n_
         if (MP_PARSE_NODE_IS_NULL(pns_except->nodes[0])) {
             // this is a catch all exception handler
             if (i + 1 != n_except) {
-                compile_syntax_error(comp, pn_excepts[i], "default 'except:' must be last");
+                compile_syntax_error(comp, pn_excepts[i], "default 'except' must be last");
                 compile_decrease_except_level(comp);
                 return;
             }

py/objdict.c

@@ -386,7 +386,7 @@ STATIC mp_obj_t dict_update(size_t n_args, const mp_obj_t *args, mp_map_t *kwarg
                 if (key == MP_OBJ_STOP_ITERATION
                     || value == MP_OBJ_STOP_ITERATION
                     || stop != MP_OBJ_STOP_ITERATION) {
-                    mp_raise_ValueError("dictionary update sequence has the wrong length");
+                    mp_raise_ValueError("dict update sequence has wrong length");
                 } else {
                     mp_map_lookup(&self->map, key, MP_MAP_LOOKUP_ADD_IF_NOT_FOUND)->value = value;
                 }