README: some improvements
README: some improvements

alinasmirnova/BenchmarkDotNet,redknightlois/BenchmarkDotNet,PerfDotNet/BenchmarkDotNet,ig-sinicyn/BenchmarkDotNet,Ky7m/BenchmarkDotNet,redknightlois/BenchmarkDotNet,Ky7m/BenchmarkDotNet,ig-sinicyn/BenchmarkDotNet,Teknikaali/BenchmarkDotNet,ig-sinicyn/BenchmarkDotNet,alinasmirnova/BenchmarkDotNet,Teknikaali/BenchmarkDotNet,PerfDotNet/BenchmarkDotNet,adamsitnik/BenchmarkDotNet,Ky7m/BenchmarkDotNet,Teknikaali/BenchmarkDotNet,adamsitnik/BenchmarkDotNet,ig-sinicyn/BenchmarkDotNet,redknightlois/BenchmarkDotNet,adamsitnik/BenchmarkDotNet,Ky7m/BenchmarkDotNet,alinasmirnova/BenchmarkDotNet,PerfDotNet/BenchmarkDotNet,alinasmirnova/BenchmarkDotNet,adamsitnik/BenchmarkDotNet