fix: links in readme (#321)

Author: sjvans

README.md

@@ -38,9 +38,9 @@ Documentation can be found at [cap.cloud.sap](https://cap.cloud.sap/docs) and [o
   - [Sampler](#sampler)
   - [Propagators](#propagators)
   - [Exporters](#exporters)
-  - [High Resolution Timestamps (beta)](#high-resolution-timestamps)
+  - [High Resolution Timestamps (beta)](#high-resolution-timestamps-beta)
   - [Environment Variables](#environment-variables)
-- [Custom Spans (beta)](#custom-spans)
+- [Custom Spans (beta)](#custom-spans-beta)
 - [Support, Feedback, Contributing](#support-feedback-contributing)
 - [Code of Conduct](#code-of-conduct)
 - [Licensing](#licensing)
@@ -477,7 +477,7 @@ Default:
     ```
 
 
-### High Resolution Timestamps (beta) {#high-resolution-timestamps}
+### High Resolution Timestamps (beta)
 
 By default, the start time of a span is taken from `Date.now()` and, hence, has only millisecond resolution.
 Via `cds.requires.telemetry.tracing.hrtime = true`, you can instruct the plugin to specify the start and end times of spans, which it does with nanosecond resolution.
@@ -500,7 +500,7 @@ Please note that `process.env.VCAP_APPLICATION` and `process.env.CF_INSTANCE_GUI
 
 
 
-## Custom Spans (beta) {#custom-spans}
+## Custom Spans (beta)
 
 Custom spans can be added to the trace hierarchy via [`tracer.startActiveSpan()`](https://open-telemetry.github.io/opentelemetry-js/interfaces/_opentelemetry_api.Tracer.html#startActiveSpan).
 For this, you need to create your own tracer via [TraceAPI.getTracer()](https://open-telemetry.github.io/opentelemetry-js/classes/_opentelemetry_api.TraceAPI.html#getTracer).