Added docs generation

Author: egil

src/AngleSharp.Diffing.nuspec

@@ -16,6 +16,7 @@
     <dependencies>
       <group targetFramework="netstandard2.0">
         <dependency id="AngleSharp" version="0.13.0" />
+        <dependency id="AngleSharp.Css" version="0.13.0" />
       </group>
     </dependencies>
   </metadata>

src/AngleSharp.Diffing.sln

@@ -9,6 +9,7 @@ Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "AngleSharp.DiffingTests", "
 EndProject
 Project("{2150E333-8FDC-42A3-9474-1A3956D46DE8}") = "Solution Items", "Solution Items", "{E8E3C8B4-92C3-4DB7-B920-D28651E24A57}"
 	ProjectSection(SolutionItems) = preProject
+		..\tools\anglesharp.cake = ..\tools\anglesharp.cake
 		AngleSharp.Diffing.nuspec = AngleSharp.Diffing.nuspec
 		Directory.Build.props = Directory.Build.props
 	EndProjectSection

src/AngleSharp.Diffing/AngleSharp.Diffing.csproj

@@ -4,6 +4,10 @@
     <TargetFramework>netstandard2.0</TargetFramework>
   </PropertyGroup>
 
+  <PropertyGroup Condition="'$(Configuration)'=='Release'">
+    <GenerateDocumentationFile>true</GenerateDocumentationFile>
+  </PropertyGroup>
+
   <ItemGroup>
     <PackageReference Include="AngleSharp" Version="$(AngleSharpVersion)" />
     <PackageReference Include="AngleSharp.Css" Version="$(AngleSharpVersion)" />