Handle Pageable POST params as query maps. Update docs. Fixes gh-753.

docs/src/main/asciidoc/spring-cloud-openfeign.adoc

@@ -758,17 +758,15 @@ In the following example, the `CSV` format is used instead of the default `EXPLO
 [source,java,indent=0]
 ----
 @FeignClient(name = "demo")
-protected interface PageableFeignClient {
+protected interface DemoFeignClient {
 
     @CollectionFormat(feign.CollectionFormat.CSV)
-    @GetMapping(path = "/page")
-    ResponseEntity performRequest(Pageable page);
+    @GetMapping(path = "/test")
+    ResponseEntity performRequest(String test);
 
 }
 ----
 
-TIP: Set the `CSV` format while sending `Pageable` as a query parameter in order for it to be encoded correctly.
-
 === Reactive Support
 As the https://github.com/OpenFeign/feign[OpenFeign project] does not currently support reactive clients, such as https://docs.spring.io/spring/docs/current/javadoc-api/org/springframework/web/reactive/function/client/WebClient.html[Spring WebClient], neither does Spring Cloud OpenFeign.We will add support for it here as soon as it becomes available in the core project.