Remove links from heading text in readme

These links result in invalid markup in the automatically generated table of contents.

They were not essential in any way and it is probably not a great idea to put links in headings anyway so they are
removed.

Author: per1234

README.md

@@ -39,15 +39,15 @@ This action comments on the pull request with a report on the resulting change i
 
 The action can be used in two ways:
 
-#### Run from a [scheduled workflow](https://help.github.com/en/actions/reference/workflow-syntax-for-github-actions#onschedule)
+#### Run from a scheduled workflow
 
 Recommended for public repositories.
 
-The use of a scheduled workflow is necessary in order for the action to have the [write permissions required to comment on pull requests submitted from forks](https://help.github.com/en/actions/configuring-and-managing-workflows/authenticating-with-the-github_token).
+The use of a [scheduled workflow](https://help.github.com/en/actions/reference/workflow-syntax-for-github-actions#onschedule) is necessary in order for the action to have the [write permissions required to comment on pull requests submitted from forks](https://help.github.com/en/actions/configuring-and-managing-workflows/authenticating-with-the-github_token).
 
 In this usage, the `sketches-reports-source` defines the name of the workflow artifact that contains the memory usage data, as specified to the [`actions/upload-artifact`](https://github.com/actions/upload-artifact) action via its `name` input.
 
-#### Run from the same workflow as the [`arduino/compile-sketches`](https://github.com/arduino/compile-sketches) action
+#### Run from the same workflow as the `arduino/compile-sketches` action
 
 Recommended for private repositories.