Merge the enqueue changesets into one

The last few releases added enqueue instrumentation one library at a
time, each with its own changeset. They now ship together in one minor
release, so combine them into a single changeset that lists every
library. No changelog entry is lost, it is just told as one story.

Author: unflxw

.changesets/add-delayed-job-enqueue-instrumentation.md

@@ -0,0 +1,24 @@
+---
+bump: minor
+type: add
+---
+
+Instrument background job enqueues. Enqueuing a job now records an enqueue
+event on the active transaction, so enqueues made from within a web request or
+another job show up in the event timeline. This is recorded for Sidekiq
+(`enqueue.sidekiq`), Que (`enqueue.que`, plus `bulk_enqueue.que` for bulk
+enqueues on Que 2), Resque (`enqueue.resque`), Shoryuken (`enqueue.shoryuken`)
+and Delayed Job (`enqueue.delayed_job`). Each event is titled after the job
+being enqueued.
+
+For Active Job, the `enqueue.active_job` event is now recorded by AppSignal's
+own instrumentation rather than by Rails' native `enqueue.active_job`
+notification. The native notification is suppressed so the enqueue is recorded
+once, and the event is now titled after the job being enqueued.
+
+These enqueue events can be turned off with the
+`enable_job_enqueue_instrumentation` config option. Set it to `false` to stop
+recording enqueue events across all integrations, without affecting the
+instrumentation of the jobs themselves. It defaults to `true` and can also be
+set through the `APPSIGNAL_ENABLE_JOB_ENQUEUE_INSTRUMENTATION` environment
+variable.