修复 label 名格式提示,只允许字符、数字、下划线

src/common/pl/plpgsql/src/gram.y

@@ -9775,7 +9775,7 @@ make_execsql_stmt(int firsttoken, int location)
     bool insert_array_record = false; 
     int values_end_loc = -1;
     int before_semi_loc = -1;
-    const char* err_msg = "The lable name is invalid";
+    const char* err_msg = "The label name can only contain letters, digits and underscores";
     PLpgSQL_row* row_data = NULL;
     PLpgSQL_rec* rec_data = NULL;
     PLpgSQL_var* array_data = NULL;

src/test/regress/expected/b_compatibility.out

@@ -1221,7 +1221,7 @@ insert into tb_1092829 values(n);
 END loop;
 END;
 /
-ERROR:  The lable name is invalid
+ERROR:  The label name can only contain letters, digits and underscores
 LINE 2: “abel1*”:
         ^
 QUERY:   DECLARE BEGIN
@@ -1248,7 +1248,7 @@ insert into tb_1092829 values(n);
 END loop;
 END;
 /
-ERROR:  The lable name is invalid
+ERROR:  The label name can only contain letters, digits and underscores
 LINE 2: label#:
              ^
 QUERY:   DECLARE BEGIN
@@ -1275,7 +1275,7 @@ insert into tb_1092829 values(n);
 END loop;
 END;
 /
-ERROR:  The lable name is invalid
+ERROR:  The label name can only contain letters, digits and underscores
 LINE 2: 测试中文:
         ^
 QUERY:   DECLARE BEGIN