Add workflow to verify markdown links (#368)

Add workflow to verify markdown links. 
Remove outdated CHANGES file.
Fix and remove broken links.

.github/workflows/markdown-link-check-config.json

@@ -0,0 +1,18 @@
+{
+  "ignorePatterns": [
+  ],
+  "replacementPatterns": [
+    {
+      "pattern": "^/",
+      "replacement": "{{BASEURL}}/"
+    }
+  ],
+  "httpHeaders": [
+    {
+      "urls": ["https://docs.github.com/"],
+      "headers": {
+        "Accept-Encoding": "zstd, br, gzip, deflate"
+      }
+    }
+  ]
+}

.github/workflows/markdown-link-check.yml

@@ -0,0 +1,18 @@
+name: markdown-link-check
+on: [push, pull_request]
+
+jobs:
+  markdown-link-check:
+    name: markdown-link-check
+    runs-on: ubuntu-latest
+
+    steps:
+    - name: Clone the repository
+      uses: actions/checkout@96f53100ba2a5449eb71d2e6604bbcd94b9449b5
+
+    - name: Validate Markdown links
+      uses: gaurav-nelson/github-action-markdown-link-check@322b2315689b8cc8c65c14a07064ec862e62ee7c
+      with:
+        use-quiet-mode: 'yes'
+        # https://github.com/tcort/markdown-link-check#config-file-format
+        config-file: '.github/workflows/markdown-link-check-config.json'

README.md

@@ -52,8 +52,6 @@ You may file doc bugs [here][docbugs].
 
 [![Join the chat at https://gitter.im/Microsoft/extendvs](https://badges.gitter.im/Join%20Chat.svg)](https://gitter.im/Microsoft/extendvs?utm_source=badge&utm_medium=badge&utm_campaign=pr-badge&utm_content=badge)
 
-For the latest features take a look at [Changes][changes].
-
 For further information about extending Visual Studio in other ways please check out
 [Visual Studio extensibility documentation][3].
 
@@ -66,6 +64,5 @@ This project has adopted the [Microsoft Open Source Code of Conduct](https://ope
  [VSSDK]: https://go.microsoft.com/?linkid=9877247
  [prereq]: doc/overview/prereqs.md
  [intro]: doc/overview/intro.md
- [changes]: CHANGES.md
  [docbugs]: https://github.com/Microsoft/VSProjectSystem/issues
 

doc/Index.md

@@ -83,7 +83,6 @@ VS Project System Documentation
      - [Who holds a project lock?](scenario/who_holds_a_project_lock.md)
   - [Turn on CPS for a C#/VB project](scenario/turn_on_cps_for_csharp_vb_project.md)
   - [Add Single File Generator](scenario/add_single_file_generator.md)
-- [Changes](../CHANGES.md)
 - Breaking changes
   - [Breaking Changes in Visual Studio 2019](overview/breaking_changes_visual_studio_2019.md)
   - [Breaking Changes in Visual Studio 2017](overview/breaking_changes_visual_studio_2017.md)

doc/extensibility/IDebugLaunchProvider.md

@@ -112,15 +112,5 @@ There are different extensions for each version of VS. Downloading the
 extension and creating a project from its project template will pop up 
 a README file that explains how to use it.
 
-- [Visual C++ 2015 Debugger Launch Extension][1]
-- [Visual C++ 2013 Debugger Launch Extension][2]
-- [Visual C++ 2012 Debugger Launch Extension][3]
-- [Visual C++ 2010 Debugger Launch Extension][4]
-
 Consider renaming debugger class (or rule file) so they don't collide
-(namespace is the only distinguisher)
-
- [1]: https://visualstudiogallery.msdn.microsoft.com/7fe7f19f-ceb9-47e3-b440-c62df2b85281
- [2]: https://visualstudiogallery.msdn.microsoft.com/e831676e-9510-4651-b724-cf4299b220b5
- [3]: https://visualstudiogallery.msdn.microsoft.com/8d2faf2c-3937-489a-9e0a-c43ff26ca427
- [4]: https://visualstudiogallery.msdn.microsoft.com/f1e9c8b5-134e-4bb1-bd0e-37a220dae99e
+(namespace is the only distinguisher).

doc/overview/prereqs.md

@@ -7,4 +7,4 @@ Install these prequisites before writing project system extensions:
    * .NET Desktop development
    * Visual Studio extension development
    * .NET Core and Docker - project system based on CPS
-3. Install [Visual Studio Project System Extensibility Preview](https://visualstudiogallery.msdn.microsoft.com/43691584-1f0f-46da-adaf-a07c290c1e6e)
+3. Install [Visual Studio Project System Extensibility Preview](https://marketplace.visualstudio.com/items?itemName=VisualStudioProductTeam.VisualStudioProjectSystemExtensibilityPreview-13433)