[prometheus] Stabilize SDK exporter port config

Author: johannaojeling

CHANGELOG.md

@@ -80,6 +80,8 @@ release.
 - Stabilize sections of Prometheus Metrics Exporter.
   - Stabilize host configuration.
     ([#4984](https://github.com/open-telemetry/opentelemetry-specification/issues/4984))
+  - Stabilize port configuration.
+    ([#4985](https://github.com/open-telemetry/opentelemetry-specification/issues/4985))
 
 ### SDK Configuration
 

specification/metrics/sdk_exporters/prometheus.md

@@ -110,7 +110,7 @@ by default.
 
 ### Port
 
-**Status**: [Development](../../document-status.md)
+**Status**: [Stable](../../document-status.md)
 
 A Prometheus Exporter SHOULD support a configuration option to set the port
 that metrics are served on. The option MAY be named `port`, and MUST be `9464` by