small tweak to referring to the "built-in" attributes as "default"

extension/opampextension/README.md

@@ -31,7 +31,7 @@ The following settings are optional:
 - `capabilities`: Keys with boolean true/false values that enable a particular OpAMP capability.
   - `reports_effective_config`: Whether to enable the OpAMP ReportsEffectiveConfig capability. Default is `true`.
 - `agent_description`: Setting that modify the agent description reported to the OpAMP server.
-  - `non_identifying_attributes`: A map of key value pairs that will be added to the [non-identifying attributes](https://github.com/open-telemetry/opamp-spec/blob/main/specification.md#agentdescriptionnon_identifying_attributes) reported to the OpAMP server. If an attribute collides with the built-in non identifying attributes that are automatically added, the ones specified here take precedence.
+  - `non_identifying_attributes`: A map of key value pairs that will be added to the [non-identifying attributes](https://github.com/open-telemetry/opamp-spec/blob/main/specification.md#agentdescriptionnon_identifying_attributes) reported to the OpAMP server. If an attribute collides with the default non identifying attributes that are automatically added, the ones specified here take precedence.
 
 ### Example