add content about workflow availability

Author: mchammer01

content/github/finding-security-vulnerabilities-and-errors-in-your-code/setting-up-code-scanning-for-a-repository.md

@@ -31,8 +31,9 @@ You decide how to generate {% data variables.product.prodname_code_scanning %} a
 {% data reusables.repositories.sidebar-security %}
 3. To the right of "{% data variables.product.prodname_code_scanning_capc %} alerts", click **Set up {% data variables.product.prodname_code_scanning %}**. {% if currentVersion == "free-pro-team@latest" or currentVersion ver_gt "enterprise-server@3.0" %}If {% data variables.product.prodname_code_scanning %} is missing, you need to ask an organization owner or repository administrator to enable {% data variables.product.prodname_GH_advanced_security %}. For more information, see "[Managing security and analysis settings for your organization](/github/setting-up-and-managing-organizations-and-teams/managing-security-and-analysis-settings-for-your-organization)" or "[Managing security and analysis settings for your repository](/github/administering-a-repository/managing-security-and-analysis-settings-for-your-repository)."{% endif %}
  !["Set up {% data variables.product.prodname_code_scanning %}" button to the right of "{% data variables.product.prodname_code_scanning_capc %}" in the Security Overview](/assets/images/help/security/overview-set-up-code-scanning.png)
-4. Under "Get started with {% data variables.product.prodname_code_scanning %}", click **Set up this workflow** on the {% data variables.product.prodname_codeql_workflow %} or on a third-party workflow.
+4. Under "Get started with {% data variables.product.prodname_code_scanning %}", click **Set up this workflow** on the {% data variables.product.prodname_codeql_workflow %} or on a third-party workflow. 
  !["Set up this workflow" button under "Get started with {% data variables.product.prodname_code_scanning %}" heading](/assets/images/help/repository/code-scanning-set-up-this-workflow.png)
+ Most workflows are unavailable if they aren't relevant for the programming languages detected in the repository. The only exception is the {% data variables.product.prodname_codeql_workflow %}, which is always displayed, but the "Set up this workflow" button will be disabled if the languages in the repository are not supported by the {% data variables.product.prodname_codeql %} analysis.
 5. To customize how {% data variables.product.prodname_code_scanning %} scans your code, edit the workflow.
 
    Generally you can commit the {% data variables.product.prodname_codeql_workflow %} without making any changes to it. However, many of the third-party workflows require additional configuration, so read the comments in the workflow before committing.