Update templates.asciidoc
Dropped in a few links to index settings and mappings to make things easier to jump to.
== Index Templates
Index templates allow you to define templates that will automatically be
-applied when new indices are created. The templates include both settings and
-mappings, and a list of patterns that control whether the template should be
+applied when new indices are created. The templates include both
+<<index-modules-settings,settings>> and <<mapping,mappings>>
+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
