getAcceptLanguageAsLocale(s) returns most preferred Locale

An update on the last commit switching from:
List<Locale> getAcceptLanguageAsLocales() to
Locale getAcceptLanguageAsLocale()

This best supports the scenario for the most preferred Locale.
If there is a need to look at the prioritized list of languages it's
best to use Locale.filter with the LocaleRange's.

This is explained in the Javadoc for getAcceptLanguage().

Issue: SPR-15024

spring-web/src/test/java/org/springframework/http/HttpHeadersTests.java

@@ -437,13 +437,7 @@ public class HttpHeadersTests {
 		);
 		assertEquals(expectedRanges, headers.getAcceptLanguage());
 
-		List<Locale> expectedLocales = Arrays.asList(
-				Locale.forLanguageTag("fr-ch"),
-				Locale.forLanguageTag("fr"),
-				Locale.forLanguageTag("en"),
-				Locale.forLanguageTag("de")
-		);
-		assertEquals(expectedLocales, headers.getAcceptLanguageAsLocales());
+		assertEquals(Locale.forLanguageTag("fr-ch"), headers.getAcceptLanguageAsLocale());
 	}
 
 	@Test