Fix web session javadoc typo

See gh-39821

Author: Roiocam

spring-boot-project/spring-boot/src/main/java/org/springframework/boot/web/servlet/server/Session.java

@@ -104,7 +104,7 @@ SessionStoreDirectory getSessionStoreDirectory() {
 
 	/**
 	 * Session cookie properties. This class is provided only for back-compatibility
-	 * reasons, consider using {@link org.springframework.boot.web.server.Cookie} whever
+	 * reasons, consider using {@link org.springframework.boot.web.server.Cookie} whenever
 	 * possible.
 	 */
 	public static class Cookie extends org.springframework.boot.web.server.Cookie {