Update reference documentation with examples that match @EnableMapRepositories.

Closes #358
Original pull request: #364.

Author: sdavids

src/main/asciidoc/key-value-repositories.adoc

@@ -51,7 +51,7 @@ You can use a different type or preinitialize the adapter with some values, and
 [source, java]
 ----
 @Bean
-public KeyValueOperations keyValueTemplate() {
+public KeyValueOperations mapKeyValueTemplate() {
   return new KeyValueTemplate(keyValueAdapter());
 }
 
@@ -61,6 +61,8 @@ public KeyValueAdapter keyValueAdapter() {
 }
 ----
 
+Alternatively, you might use `@EnableMapRepositories(keyValueTemplateRef=…)`.
+
 [[key-value.keyspaces]]
 == Keyspaces