IMO both docs are in the right places, moreover howto/static-files/index.txt mentions namespaces in the Static file namespacing admonition. Nevertheless adding a cross reference to the docs/ref/settings.txt seems like a good idea, e.g.
--- a/docs/howto/static-files/index.txt
+++ b/docs/howto/static-files/index.txt
distinguish between them. We need to be able to point Django at the right
- one, and the best way to ensure this is by *namespacing* them. That is,
- by putting those static files inside *another* directory named for the
- application itself.
+ one, and the best way to ensure this is by :ref:`namespacing them
+ <staticfiles-dirs-prefixes>`. That is, by putting those static files inside
+ *another* directory named for the application itself.
--- a/docs/ref/settings.txt
+++ b/docs/ref/settings.txt
+.. _staticfiles-dirs-prefixes:
+
Prefixes (optional)
~~~~~~~~~~~~~~~~~~~
The reason why I speak of prefixes in particular is because I had a particular case where I needed them to be served as static files and at the same time include them in a meaningful directory structure of my code repository. The default action is the contents of the files are moved to the STATIC_ROOT folder. Using prefixes meant I could namespace the static files properly and hence link to them (from outside templates) using straight forward and intutive links.