chore: Link fix (#4913)

Fixes #

## Changes

This fixes the link to a section/heading which was changed as part of
#4887

For non-trivial changes, follow the [change proposal
process](https://github.com/open-telemetry/opentelemetry-specification/blob/main/CONTRIBUTING.md#proposing-a-change).

* [ ] Related issues #
* [ ] Related [OTEP(s)](https://github.com/open-telemetry/oteps) #
* [ ] Links to the prototypes (when adding or changing features)
* [ ]
[`CHANGELOG.md`](https://github.com/open-telemetry/opentelemetry-specification/blob/main/CHANGELOG.md)
file updated for non-trivial changes
* For trivial changes, include `[chore]` in the PR title to skip the
changelog check
* [ ] [Spec compliance
matrix](https://github.com/open-telemetry/opentelemetry-specification/blob/main/spec-compliance-matrix/template.yaml)
updated if necessary

Author: thompson-tomo

specification/library-guidelines.md

@@ -133,4 +133,4 @@ safeties should API implementations provide and how they should be documented:
 
 * [Metrics API](./metrics/api.md#concurrency-requirements)
 * [Metrics SDK](./metrics/sdk.md#concurrency-requirements)
-* [Tracing API](./trace/api.md#concurrency)
+* [Tracing API](./trace/api.md#concurrency-requirements)