Make Directory.Build.props readable.

Directory.Build.props

@@ -1,12 +1,29 @@
 <Project>
   <PropertyGroup>
+
+    <!-- All Microsoft packages -->
     <MicrosoftPackageVersion>5.0.0</MicrosoftPackageVersion>
+
+    <!-- Microsoft.NET.Test.Sdk https://www.nuget.org/packages/Microsoft.NET.Test.Sdk -->
     <MicrosoftNETTestSdkPackageVersion>16.6.1</MicrosoftNETTestSdkPackageVersion>
+
+    <!-- NSubstitute  https://www.nuget.org/packages/NSubstitute -->
     <NSubstitutePackageVersion>4.2.2</NSubstitutePackageVersion>
+
+    <!-- Shouldly https://www.nuget.org/packages/Shouldly -->
     <ShouldlyPackageVersion>3.0.2</ShouldlyPackageVersion>
+
+    <!-- xunit https://www.nuget.org/packages/xUnit -->
     <xUnitPackageVersion>2.4.1</xUnitPackageVersion>
+
+    <!-- xunit.extensibility.execution https://www.nuget.org/packages/xunit.extensibility.execution -->
     <xUnitExtensibilityExecutionPackageVersion>2.4.1</xUnitExtensibilityExecutionPackageVersion>
+
+    <!-- xunit.runner.visualstudio https://www.nuget.org/packages/xunit.runner.visualstudio -->
     <xUnitRunnerVisualstudioPackageVersion>2.4.2</xUnitRunnerVisualstudioPackageVersion>
+
+    <!-- Mongo2Go https://www.nuget.org/packages/Mongo2Go -->
     <Mongo2GoPackageVersion>2.2.14</Mongo2GoPackageVersion>
+
   </PropertyGroup>
 </Project>