Remove links to Jetty API and documentation

This commit removes links to Jetty API and documentation as those links
are breaking every time the Jetty team releases a new version

See https://github.com/eclipse/jetty.project/issues/4546

Closes gh-24493

spring-boot-project/spring-boot-docs/pom.xml

@@ -1195,7 +1195,6 @@
 										<link>https://docs.spring.io/spring-framework/docs/${spring-framework.version}/javadoc-api/</link>
 										<link>https://docs.spring.io/spring-security/site/docs/${spring-security.version}/api/</link>
 										<link>https://tomcat.apache.org/tomcat-9.0-doc/api/</link>
-										<link>https://www.eclipse.org/jetty/javadoc/${jetty.version}/</link>
 										<link>https://www.thymeleaf.org/apidocs/thymeleaf/${thymeleaf.version}/</link>
 									</links>
 								</configuration>

spring-boot-project/spring-boot-docs/src/main/asciidoc/attributes.adoc

@@ -98,7 +98,6 @@
 :gradle-docs: https://docs.gradle.org/current/userguide
 :hibernate-docs: https://docs.jboss.org/hibernate/orm/5.4/userguide/html_single/Hibernate_User_Guide.html
 :java-api: https://docs.oracle.com/javase/8/docs/api/
-:jetty-docs: https://www.eclipse.org/jetty/documentation/{jetty-version}
 :jooq-docs: https://www.jooq.org/doc/{jooq-version}/manual-single-page
 :junit5-docs: https://junit.org/junit5/docs/current/user-guide
 :kotlin-docs: https://kotlinlang.org/docs/reference/

spring-boot-project/spring-boot-docs/src/main/asciidoc/howto.adoc

@@ -837,7 +837,7 @@ Finally, access logging for Jetty can also be configured as follows:
 ----
 
 By default, logs are redirected to `System.err`.
-For more details, see {jetty-docs}/configuring-jetty-request-logs.html[the Jetty documentation].
+For more details, see the Jetty documentation.