fix(MeshService): namespace on example (#1952)

* fix(MeshService): namespace on example
* feat(policy_yaml): add namespace param for namespaced policies/resources

Signed-off-by: Mike Beaumont <mjboamail@gmail.com>

app/_src/networking/meshservice.md

@@ -18,7 +18,7 @@ the analog of a Kubernetes `Service`.
 
 A basic example follows to illustrate the structure:
 
-{% policy_yaml meshservice_example %}
+{% policy_yaml meshservice_example namespace=kuma-demo %}
 ```yaml
 type: MeshService
 name: redis
@@ -29,7 +29,7 @@ spec:
   selector:
     dataplaneTags: # tags in Dataplane object, see below
       app: redis
-      k8s.kuma.io/namespace: redis-system # added automatically
+      k8s.kuma.io/namespace: kuma-demo # added automatically
   ports:
   - port: 6739
     targetPort: 6739

jekyll-kuma-plugins/lib/jekyll/kuma-plugins/liquid/tags/policyyaml.rb

@@ -62,7 +62,7 @@ def render(context)
             # remove ```yaml header and ``` footer and read each document one by one
             content = content.gsub(/`{3}yaml\n/, '').gsub(/`{3}/, '')
             site_data = context.registers[:site].config
-            mesh_namespace = site_data['mesh_namespace']
+            mesh_namespace = @params["namespace"] || site_data['mesh_namespace']
             uni_content = ""
             kube_content = ""
             YAML.load_stream(content) do |yaml_data|