Add link to TIOBE Index on main page + fix issues (#1137)

* Add TIOBE + include SonarAnalyzer.CSharp

* .

* cp

* Copyright © WireMock.Net

* more fixes

* fix

* xpath

* if (Matchers == null || !Matchers.Any())

* if (Matchers != null)

* ?

* .

* .

src/WireMock.Net.xUnit/TestOutputHelperWireMockLogger.cs

@@ -1,3 +1,5 @@
+// Copyright © WireMock.Net
+
 using System;
 using Newtonsoft.Json;
 using Stef.Validation;

src/WireMock.Net.xUnit/WireMock.Net.xUnit.csproj

@@ -25,7 +25,6 @@
     </PropertyGroup>
 
     <ItemGroup>
-        <PackageReference Include="Microsoft.SourceLink.GitHub" Version="1.1.1" PrivateAssets="All" />
         <PackageReference Include="Newtonsoft.Json" Version="13.0.3" />
         <PackageReference Include="Stef.Validation" Version="0.1.1" />
         <PackageReference Include="xUnit.abstractions" Version="2.0.3" />