Title the Active Job enqueue event with the job

The `enqueue.active_job` event carries an "enqueue <Class> job" title
so the timeline shows which job was enqueued.

Author: unflxw

.changesets/instrument-active-job-enqueues.md

@@ -7,4 +7,4 @@ Record the `enqueue.active_job` event from AppSignal's own Active Job
 instrumentation rather than from Rails' native `enqueue.active_job`
 notification, which is now suppressed so the enqueue is recorded once. The
 event still shows up on the active transaction when enqueuing from within a web
-request or another job; there is no change to what you see.
+request or another job, and is now titled after the job being enqueued.

lib/appsignal/hooks/active_job.rb

@@ -56,7 +56,7 @@ def install
       # @!visibility private
       module ActiveJobEnqueueInstrumentation
         def enqueue(*, **)
-          Appsignal.instrument("enqueue.active_job") do
+          Appsignal.instrument("enqueue.active_job", "enqueue #{self.class.name} job") do
             # Active Job enqueues through an adapter (Sidekiq, Resque, ...) that
             # has its own enqueue instrumentation. Suppress it so the enqueue is
             # recorded once, as this event, rather than as nested Active Job +

spec/lib/appsignal/hooks/activejob_spec.rb

@@ -346,8 +346,11 @@ def perform(*_args)
 
           # Exactly one enqueue event: ours. Rails' native `enqueue.active_job`
           # notification is suppressed so it isn't recorded a second time.
-          event_names = transaction.to_h["events"].map { |event| event["name"] }
-          expect(event_names.count("enqueue.active_job")).to eq(1)
+          enqueue_events =
+            transaction.to_h["events"].select { |event| event["name"] == "enqueue.active_job" }
+          expect(enqueue_events.size).to eq(1)
+          # The event is titled after the job being enqueued.
+          expect(enqueue_events.first["title"]).to eq("enqueue ActiveJobTestJob job")
         end
       end