Fix admonition extension

docs/merlin6/introduction.md

@@ -1,5 +1,10 @@
 # About Merlin6
 
-Merlin6 is **no longer accessible for new users** and a smaller footprint of it has been kept for some of the stakeholder which owned nodes and can not fully run on the new cluster!
+!!! warning "Merlin6 availability"
+    **Merlin6 is closed to new users.**
+
+    Only a reduced footprint of Merlin6 is still maintained, and **exclusively** for a small number of stakeholders
+    who own dedicated nodes and cannot yet fully run their workloads on the new cluster.
+
+    **New users must request access to Merlin7 instead.**
 
-Please have a look at [Merlin 7](../merlin7/01-Quick-Start-Guide/introduction.md) instead.

mkdocs.yml

@@ -78,7 +78,10 @@ markdown_extensions:
   - pymdownx.keys
   - pymdownx.mark
   - pymdownx.snippets
-  - pymdownx.superfences
+  - pymdownx.superfences:
+      custom_fences:
+        - name: mermaid
+          class: mermaid
   - pymdownx.tilde
 
 # Page tree
@@ -190,9 +193,3 @@ nav:
     - support/faq.md
     - support/known-problems.md
     - support/troubleshooting.md
-
-markdown_extensions:
-  - pymdownx.superfences:
-      custom_fences:
-        - name: mermaid
-          class: mermaid