Update advanced.qmd

The code shown is not the same as the "demo/mini/absolute.qmd".

(cherry picked from commit 55af649)

Author: yyzeng

docs/presentations/revealjs/advanced.qmd

@@ -154,7 +154,7 @@ For example, here we add the `.absolute` class to three images and give them eac
 
 ![](image2.png){.absolute top=50 right=50 width="450" height="250"}
 
-![](image3.png){.absolute bottom=0 right=50 width="300" height="300"}
+![](image3.png){.absolute bottom=20 right=100 width="300" height="300"}
 ```
 
 The following attributes can be used with `absolute`. All of these values can be specified in CSS units (e.g. `px`, `em`, etc.). If a number with no units is specified (as in the above example) then pixels are assumed.