Clarify Pulsar instrumentation scope (#14875)

Author: trask

instrumentation/pulsar/pulsar-2.8/README.md

@@ -1,5 +1,8 @@
 # Settings for the Apache Pulsar instrumentation
 
+This instrumentation applies to the Pulsar Java client library only. It does not instrument
+Pulsar server components (broker, functions, etc.).
+
 | System property                                            | Type    | Default | Description                                         |
 | ---------------------------------------------------------- | ------- | ------- | --------------------------------------------------- |
 | `otel.instrumentation.pulsar.experimental-span-attributes` | Boolean | `false` | Enable the capture of experimental span attributes. |