Enable concurrent execution for thread-safe analyzers

Author: sharwell

StyleCop.Analyzers/StyleCop.Analyzers/MaintainabilityRules/SA1404CodeAnalysisSuppressionMustHaveJustification.cs

@@ -60,6 +60,7 @@ internal class SA1404CodeAnalysisSuppressionMustHaveJustification : DiagnosticAn
         public override void Initialize(AnalysisContext context)
         {
             context.ConfigureGeneratedCodeAnalysis(GeneratedCodeAnalysisFlags.None);
+            context.EnableConcurrentExecution();
 
             context.RegisterCompilationStartAction(CompilationStartAction);
         }

StyleCop.Analyzers/StyleCop.Analyzers/ReadabilityRules/SA1121UseBuiltInTypeAlias.cs

@@ -143,6 +143,7 @@ internal class SA1121UseBuiltInTypeAlias : DiagnosticAnalyzer
         public override void Initialize(AnalysisContext context)
         {
             context.ConfigureGeneratedCodeAnalysis(GeneratedCodeAnalysisFlags.None);
+            context.EnableConcurrentExecution();
 
             context.RegisterCompilationStartAction(CompilationStartAction);
         }

StyleCop.Analyzers/StyleCop.Analyzers/SpecialRules/SA0001XmlCommentAnalysisDisabled.cs

@@ -39,6 +39,7 @@ internal class SA0001XmlCommentAnalysisDisabled : DiagnosticAnalyzer
         public override void Initialize(AnalysisContext context)
         {
             context.ConfigureGeneratedCodeAnalysis(GeneratedCodeAnalysisFlags.None);
+            context.EnableConcurrentExecution();
 
             context.RegisterCompilationStartAction(CompilationStartAction);
         }