Add PR number to changelog entry

Author: MrAlias

CHANGELOG.md

@@ -14,7 +14,7 @@ This project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.htm
 
 ### Removed
 
-- The deprecated `go.opentelemetry.io/contrib/processors/baggagecopy` package is removed. (#TBD)
+- The deprecated `go.opentelemetry.io/contrib/processors/baggagecopy` package is removed. (#5853)
 
 ## [1.28.0/0.53.0/0.22.0/0.8.0/0.3.0/0.1.0] - 2024-07-02