Fix missing explanation for resource type indicator in reference docs.

Author: Mikołaj Matuszewski

src/main/asciidoc/metadata.adoc

@@ -123,6 +123,7 @@ of the attributes.
 <2> The supported operations. This one indicates how to create a new `Person`.
 <3> The `name` is `persons`, which indicates (because it is plural) that a POST should be applied to the whole collection, not a single `person`.
 <4> The `type` is `UNSAFE`, because this operation can alter the state of the system.
+<5> The `rt` is `#person-representation`, which indicates that returned resource type will be `Person` resource.
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 NOTE: This JSON document has a media type of `application/alps+json`. This is different from the previous JSON document, which had