Fix discrepancy between Version.Details.xml and Versions.props (#7314)

* Fix discrepancy between Version.Details.xml and Versions.props
* Add step to CodeCheck to ensure Version.Details.xml and Versions.props match

Author: natemcmaster

docs/ReferenceResolution.md

@@ -33,3 +33,37 @@ The requirements that led to this system are:
 * [eng/PatchConfig.props](/eng/PatchConfig.props) - lists which assemblies or packages are patching in the current build.
 * [eng/ProjectReferences.props](/eng/ProjectReferences.props) - lists which assemblies or packages might be available to be referenced as a local project
 * [eng/Versions.props](/eng/Versions.props) - contains a list of versions which may be updated by automation.
+
+## Example: adding a new project
+
+Steps for adding a new project to this repo.
+
+1. Create the .csproj
+2. Run `eng/scripts/GenerateProjectList.ps1`
+3. Add it to Extensions.sln
+
+## Example: adding a new dependency
+
+Steps for adding a new package dependency to an existing project. Let's say I'm adding a dependency on System.Banana.
+
+1. Add the package to the .csproj file using `<Reference Include="System.Banana" />`
+2. Add an entry to [eng/Dependencies.props](/eng/Dependencies.props), `<LatestPackageReference Include="System.Banana" Version="0.0.1-beta-1" />`
+3. If this package comes from another dotnet team and should be updated automatically by our bot...
+    1. Change the LatestPackageReference entry to `Version="$(SystemBananaPackageVersion)"`.
+    2. Add an entry to [eng/Versions.props](/eng/Versions.props) like this `<SystemBananaPackageVersion>0.0.1-beta-1</SystemBananaPackageVersion>`.
+    3. Add an entry to [eng/Version.Details.xml](/eng/Version.Details.xml) like this:
+
+        ```xml
+        <ProductDependencies>
+          <!-- ... -->
+          </Dependency>
+            <Dependency Name="System.Banana" Version="0.0.1-beta-1">
+            <Uri>https://github.com/dotnet/corefx</Uri>
+            <Sha>000000</Sha>
+          </Dependency>
+          <!-- ... -->
+        </ProductDependencies>
+        ```
+
+       If you don't know the commit hash of the source code used to produce "0.0.1-beta-1", you can use `000000` as a placeholder for `Sha`
+       as its value is unimportant and will be updated the next time the bot runs.