Fix trailing whitespace

12_implementation/12.2_namespace.md

@@ -16,13 +16,13 @@ flowchart LR
         H4["PID 1234: nginx"]
         H5["PID 1235: nginx worker"]
     end
-    
+
     subgraph Container ["容器内视角"]
         direction TB
         C1["PID 1: nginx<br/>← 容器认为自己是 PID 1"]
         C2["PID 2: nginx worker"]
     end
-    
+
     H4 -. "（实际是宿主机的 1234）" .- C1
 ```
 
@@ -92,13 +92,13 @@ flowchart LR
         H1["eth0: 192.168.1.10<br/>端口 80 可用"]
         H2["docker0: 172.17.0.1"]
     end
-    
+
     subgraph Container ["容器"]
         direction TB
         C1["eth0: 172.17.0.2<br/>端口 80 可用"]
         C2["(veth pair 连接)"]
     end
-    
+
     H2 <--> C2
 ```