Fix broken link in examples documentation
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examples/extension/README.md
examples/extension/README.md
## Introduction
-Extensions add new features and capabilities to the agent without having to create a separate distribution (for examples and ideas, see [Use cases for extensions](#use-cases-for-extensions)).
+Extensions add new features and capabilities to the agent without having to create a separate distribution (for examples and ideas, see [Use cases for extensions](#sample-use-cases)).
The contents in this folder demonstrate how to create an extension for the OpenTelemetry Java instrumentation agent, with examples for every extension point.

Fix broken link in examples documentation (#5427)