Fix CLI command formatting

Author: anthonychu

articles/container-apps/sessions-custom-container.md

@@ -63,7 +63,7 @@ az containerapp sessionpool create \
     --registry-username <USER_NAME> \
     --registry-password <PASSWORD> \
     --container-type CustomContainer \
-    --image myregistry.azurecr.io/my-container-image:1.0 \ 
+    --image myregistry.azurecr.io/my-container-image:1.0 \
     --cpu 0.25 --memory 0.5Gi \
     --target-port 80 \
     --cooldown-period 300 \