Fixed #32004 -- Clarified docs for when request.FILES is set.

Co-authored-by: Carlton Gibson <carlton.gibson@noumenal.es>

docs/topics/http/file-uploads.txt

@@ -38,9 +38,9 @@ subclass) in the form. So the data from the above form would
 be accessible as ``request.FILES['file']``.
 
 Note that :attr:`request.FILES <django.http.HttpRequest.FILES>` will only
-contain data if the request method was ``POST`` and the ``<form>`` that posted
-the request has the attribute ``enctype="multipart/form-data"``. Otherwise,
-``request.FILES`` will be empty.
+contain data if the request method was ``POST``, at least one file field was
+actually posted, and the ``<form>`` that posted the request has the attribute
+``enctype="multipart/form-data"``. Otherwise, ``request.FILES`` will be empty.
 
 Most of the time, you'll pass the file data from ``request`` into the form as
 described in :ref:`binding-uploaded-files`. This would look something like: