subgraph: add filter condition example (#2310)

* subgraph: add filter condition example

* chore: spacing fix

* format: line break added

docs-2.0/3.ngql-guide/16.subgraph-and-path/1.get-subgraph.md

@@ -107,6 +107,20 @@ nebula> INSERT EDGE serve(start_year, end_year) VALUES "player101" -> "team204":
 
  ![GET SUBGRAPH FROM "101" OUT serve](https://docs-cdn.nebula-graph.com.cn/figures/subgraph-2-22-5-7.png)
 
+- 查询从点`player101`开始、0~2 跳、`follow`类型边`degree`大于 90，年龄大于 30 的子图，同时展示边的属性。
+
+ ```ngql
+ nebula> GET SUBGRAPH WITH PROP 2 STEPS FROM "player101" \
+ WHERE follow.degree > 90 AND $$.player.age > 30 \
+ YIELD VERTICES AS nodes, EDGES AS relationships;
+ +-------------------------------------------------------------------------------------------------------------+--------------------------------------------------------------------------------------------------------------------------------------------------------------+
+ | nodes | relationships |
+ +-------------------------------------------------------------------------------------------------------------+--------------------------------------------------------------------------------------------------------------------------------------------------------------+
+ | [("player101" :player{age: 36, name: "Tony Parker"})] | [[:follow "player101"->"player100" @0 {degree: 95}], [:follow "player101"->"player125" @0 {degree: 95}], [:follow "player100"->"player101" @0 {degree: 95}]] |
+ | [("player125" :player{age: 41, name: "Manu Ginobili"}), ("player100" :player{age: 42, name: "Tim Duncan"})] | [[:follow "player100"->"player125" @0 {degree: 95}]] |
+ +-------------------------------------------------------------------------------------------------------------+--------------------------------------------------------------------------------------------------------------------------------------------------------------+
+ ```
+
 ## FAQ
 
 ### 为什么返回结果中会出现超出`step_count`跳数之外的关系？