message: comment ngql tutorial
diff: -# nGQL Query Language
  +<!-- # nGQL Query Language
  nGQL is the query language of Nebula Graph that allows users to store and retrieve
  @@ -316,4 +316,4 @@ you to follow these syntax norms:
  |Key words | Upper case | SHOW SPACES |
  |Vertex tags | Upper camel case, beginning with an upper-case character | ManageTeam |
  |Edges | Upper snake case, beginning with an upper-case character | Play_for |
  - |Property names | Lower camel case, beginning with a lower-case character | inService | -->
  + |Property names | Lower camel case, beginning with a lower-case character | inService | --> -->
  