fix: don't nest callout

quarto-dev/quarto-cli#1112

Author: mcanouil

docs/authoring/includes.qmd

@@ -15,11 +15,8 @@ To include a file, add the `{{{< include >}}}` shortcode at the location in your
 ::: callout-important
 
 Include shortcodes are equivalent to copying and pasting the text from the included file into the main file.
-This means that relative references (links, images, etc.) inside the included file resolve based on the directory of the main file not the included file.
-
-::: {.callout-tip}
+This means that relative references (links, images, etc.) inside the included file resolve based on the directory of the main file not the included file.  
 Use absolute (to the project root) paths for links and images in included files to ensure they resolve correctly, *e.g.*, `{{< include /path/to/file.qmd >}}`.
-:::
 
 It also means that if the included file has a metadata block, that block will take effect in all included files. In most cases, having metadata blocks in an included file will cause unexpected behavior.