Deduplicate and simplify X-Device-Type example for clarity (#835)

Fixes a copy+paste mistake, it seems.

Author: jiheon2234

chapters/http-headers.adoc

@@ -409,11 +409,8 @@ request or response. Hop-by-hop headers, on the contrary, are meaningful for a
 single connection only.] and must be propagated to the services down the call
 chain. The header names and values must remain unchanged.
 
-For example, the values of the custom headers like {X-Device-Type} can affect
-the results of queries by using device type information to influence
-recommendation results. Besides, the values of the custom headers can influence
-the results of the queries (e.g. the device type information influences the
-recommendation results).
+The values of custom headers can influence query results (e.g. {X‑Device‑Type} can 
+affect recommendation results by conveying device‑type information).
 
 Sometimes the value of a proprietary header will be used as part of the entity
 in a subsequent request. In such cases, the proprietary headers must still be