Clarify settings and template on create index

This commit clarifies the interaction between settings specified in a
create index request, and those that would come from any templates that
apply to the create index request.

Relates #26994

docs/reference/indices/templates.asciidoc

@@ -8,7 +8,9 @@ and a simple pattern template that controls whether the template should be
 applied to the new index.
 
 NOTE: Templates are only applied at index creation time.  Changing a template
-will have no impact on existing indices.
+will have no impact on existing indices.  When using the create index API, the settings/mappings
+defined as part of the create index call will take precedence over any matching settings/mappings 
+defined in the template.
 
 For example: