message: Update docs according to query grammar changes
diff: @@ -91,7 +91,7 @@ to display the services' running status.
  Please make sure the services are working.
  -`bin/nebula` is a `console` which can be used to insert and query data.
  +<!-- `bin/nebula` is a `console` which can be used to insert and query data.
  `--port` is used for specifying the graph server port and the default value is `3699`.
  @@ -103,9 +103,9 @@ Run
  > bin/nebula --port=3699 -u=user -p=password
  ```
  -to connect to the graph server.
  +to connect to the graph server. -->
  -One easier way to start console is to run
  +To connect to the graph server, run
  ```
  > ./start-console.sh
  @@ -383,7 +383,7 @@ nebula> GO FROM 201 OVER like;
  Q2. Find the vertexes that 201 likes, whose age are greater than 17. Return their name, age and gender, and alias the columns as Friend, Age and Gender, respectively.
  ```
  -nebula> GO FROM 201 OVER like WHERE $$[student].age >= 17 YIELD $$[student].name AS Friend, $$[student].age AS Age, $$[student].gender AS Gender;
  +nebula> GO FROM 201 OVER like WHERE $$.student.age >= 17 YIELD $$.student.name AS Friend, $$.student.age AS Age, $$.student.gender AS Gender;
  =========================
  | Friend | Age | Gender |
  @@ -402,7 +402,7 @@ Q3. Find the courses that the vertices liked by 201 select and their grade.
  ```
  -- By pipe
  -nebula> GO FROM 201 OVER like | GO FROM $-.id OVER select YIELD $^[student].name AS Student, $$[course].name AS Course, select.grade AS Grade;
  +nebula> GO FROM 201 OVER like | GO FROM $-.id OVER select YIELD $^.student.name AS Student, $$.course.name AS Course, select.grade AS Grade;
  =============================
  | Student | Course | Grade |
  @@ -415,7 +415,7 @@ nebula> GO FROM 201 OVER like | GO FROM $-.id OVER select YIELD $^[student].name
  -----------------------------
  -- By temporary variable
  -nebula> $a=GO FROM 201 OVER like; GO FROM $a.id OVER select YIELD $^[student].name AS Student, $$[course].name AS Course, select.grade AS Grade;
  +nebula> $a=GO FROM 201 OVER like; GO FROM $a.id OVER select YIELD $^.student.name AS Student, $$.course.name AS Course, select.grade AS Grade;
  =============================
  | Student | Course | Grade |
  