Fix broken link (#22361)

* remove codeplex migrating reusable and uses of the reusable

content/github/importing-your-projects-to-github/importing-source-code-to-github/adding-an-existing-project-to-github-using-the-command-line.md

@@ -15,8 +15,6 @@ shortTitle: Add a project locally
 
 ## About adding existing projects to {% data variables.product.product_name %}
 
-{% data reusables.repositories.migrating-from-codeplex %}
-
 {% tip %}
 
 **Tip:** If you're most comfortable with a point-and-click user interface, try adding your project with {% data variables.product.prodname_desktop %}. For more information, see "[Adding a repository from your local computer to GitHub Desktop](/desktop/guides/contributing-to-projects/adding-a-repository-from-your-local-computer-to-github-desktop)" in the *{% data variables.product.prodname_desktop %} Help*.

content/github/importing-your-projects-to-github/importing-source-code-to-github/importing-a-repository-with-github-importer.md

@@ -18,8 +18,6 @@ shortTitle: Use GitHub Importer
 
 If you'd like to match the commits in your repository to the authors' GitHub user accounts during the import, make sure every contributor to your repository has a GitHub account before you begin the import.
 
-{% data reusables.repositories.migrating-from-codeplex %}
-
 {% data reusables.repositories.repo-size-limit %}
 
 1. In the upper-right corner of any page, click {% octicon "plus" aria-label="Plus symbol" %}, and then click **Import repository**.

data/reusables/repositories/migrating-from-codeplex.md

@@ -1 +0,0 @@
-If you are migrating your project from CodePlex, read the [migration guide](https://aka.ms/codeplex-guide) for more information.