Review fixes for async-http-client-1.8:javaagent (open-telemetry#17264)

Co-authored-by: otelbot <197425009+otelbot@users.noreply.github.com>

Author: otelbot[bot]

instrumentation/async-http-client/async-http-client-1.8/javaagent/src/main/java/io/opentelemetry/javaagent/instrumentation/asynchttpclient/v1_8/AsyncHttpClientInstrumentationModule.java

@@ -25,8 +25,9 @@ public AsyncHttpClientInstrumentationModule() {
 
   @Override
   public ElementMatcher.Junction<ClassLoader> classLoaderMatcher() {
-    // TimeoutsHolder class was added in 1.8.0, not present in 1.7.x
-    return hasClassesNamed("com.ning.http.client.providers.netty.timeout.TimeoutsHolder");
+    return hasClassesNamed(
+        // added in 1.8.0
+        "com.ning.http.client.providers.netty.timeout.TimeoutsHolder");
   }
 
   @Override

instrumentation/async-http-client/async-http-client-1.8/javaagent/src/main/java/io/opentelemetry/javaagent/instrumentation/asynchttpclient/v1_8/AsyncHttpClientSingletons.java

@@ -13,12 +13,12 @@
 public final class AsyncHttpClientSingletons {
   private static final String INSTRUMENTATION_NAME = "io.opentelemetry.async-http-client-1.8";
 
-  private static final Instrumenter<Request, Response> INSTRUMENTER =
+  private static final Instrumenter<Request, Response> instrumenter =
       AsyncHttpClientInstrumenterFactory.create(
           INSTRUMENTATION_NAME, AsyncHttpClient18Helper.INSTANCE);
 
   public static Instrumenter<Request, Response> instrumenter() {
-    return INSTRUMENTER;
+    return instrumenter;
   }
 
   private AsyncHttpClientSingletons() {}