Add explanation of dataset name interpolation

datasets.md

@@ -47,6 +47,12 @@ If a key is added, Pest will use the key when generating the description for the
     <img src="/assets/img/datasets-named.webp?1" style="--lines: 2" />
 </div>
 
+If the test name includes `:dataset`, the description will be interpolated into the test name at that location.
+
+<div class="code-snippet">
+    <img src="/assets/img/datasets-interpolated.webp?1" style="--lines: 2" />
+</div>
+
 It is important to notice that when using `closures` in your dataset, you must declare the arguments type in the closure passed to the test function.
 
 ```php