[reveal] Add tests for no auto stretch when aside is on slide

Author: cderv

tests/docs/reveal/stretch.qmd

@@ -234,4 +234,12 @@ Some content
 plot(cars)
 ```
 
+:::
+
+## With aside on slide  {#aside}
+
+![Caption](https://revealjs.com/images/logo/reveal-black-text.svg)
+
+::: {.aside}
+Something here as an aside
 :::

tests/smoke/render/render-reveal.test.ts

@@ -66,5 +66,6 @@ testRender(input, "revealjs", false, [
     "#custom-divs-caption img.r-stretch",
     "#custom-divs-knitr img.r-stretch",
     "#custom-divs-knitr-caption img.r-stretch",
+    "#aside img.r-stretch",
   ]),
 ]);