test: verify that HTML in admonition works

tests/format/fixtures.md

@@ -316,3 +316,29 @@ Abbreviated example from Ultralytics Documentation (https://github.com/ultralyti
 
 1. Now iterate over the results and the contours.
 .
+
+
+Deterministic indents for HTML (Snippet adapted from ULtralytics documentation)
+.
+### Object Isolation Options
+
+!!! info "Full-size Image"
+    !!! info "Inner"
+        There are no additional steps required if keeping full size image.
+
+        <figure markdown>
+             ![Example Full size Isolated Object Image Black Background](https://github.com/ultralytics/ultralytics/assets/62214284/845c00d0-52a6-4b1e-8010-4ba73e011b99){ width=240 }
+           <figcaption>Example full-size output</figcaption>
+        </figure>
+.
+### Object Isolation Options
+
+!!! info "Full-size Image"
+    !!! info "Inner"
+        There are no additional steps required if keeping full size image.
+
+        <figure markdown>
+             ![Example Full size Isolated Object Image Black Background](https://github.com/ultralytics/ultralytics/assets/62214284/845c00d0-52a6-4b1e-8010-4ba73e011b99){ width=240 }
+           <figcaption>Example full-size output</figcaption>
+        </figure>
+.