Remove the duplicated “rss” assertion

Closes gh-35139
Signed-off-by: NeatGuyCoding <[email protected]>

Author: NeatGuyCoding

spring-webmvc/src/test/java/org/springframework/web/servlet/config/annotation/WebMvcConfigurationSupportTests.java

@@ -224,7 +224,6 @@ void contentNegotiationManager() {
 		assertThat(mediaTypeMappings)
 				.containsEntry("atom", MediaType.APPLICATION_ATOM_XML)
 				.containsEntry("rss", MediaType.APPLICATION_RSS_XML)
-				.containsEntry("rss", MediaType.APPLICATION_RSS_XML)
 				.containsEntry("xml", MediaType.APPLICATION_XML)
 				.containsEntry("json", MediaType.APPLICATION_JSON)
 				.containsEntry("smile", MediaType.valueOf("application/x-jackson-smile"))