upgrade callout to warning

(cherry picked from commit b69b809)

Author: gordonwoodhull

docs/authoring/brand.qmd

@@ -726,9 +726,9 @@ local primary = brand.get_color('primary')
 
 ## Sharing brands across projects
 
-::: callout-note
+::: callout-warning
 
-Note that Quarto requires all assets, including logos and font files, to live in a single directory tree with `_quarto.yml` at the root. Using a path to a `brand.yml` file outside of that directory tree will not work correctly.
+Quarto requires all assets, including logos and font files, to live in a single directory tree with `_quarto.yml` at the root. Using a path to a `brand.yml` file outside of that directory tree will not work correctly.
 
 :::