Add admonitions to mkdocs and note to cross-namespace-references.md

Signed-off-by: Nick Young <ynick@vmware.com>

mkdocs.yml

@@ -12,6 +12,8 @@ plugins:
   - awesome-pages
   - macros:
       include_dir: examples
+markdown_extensions:
+  - admonition
 nav:
   - Introduction: index.md
   - Concepts:

site-src/v1alpha2/references/cross-namespace-references.md

@@ -10,11 +10,10 @@ In the past, we've seen that forwarding traffic across namespace boundaries is a
 desired feature, but a safeguard like ReferencePolicy,
 [vulnerabilities](https://github.com/kubernetes/kubernetes/issues/103675) can emerge.
 
-!!!note
-
+!!! note
     When discussing the process of creating cross-namespace object references, this
-    document and the documentation on the API itself refers to the object being
-    referred to as "the referent object", using the
+    document and the documentation on the API itself talk about the object being
+    referred to using the name "the referent object", using the
     [meaning](https://dictionary.cambridge.org/dictionary/english/referent)
     of "referent" to be "the person, thing, or idea that a word, phrase, or object
     refers to".