Remove the constant for the .editorconfig experiment

This constant was no longer used.

src/Features/Core/Portable/CodeFixes/Configuration/ConfigureCodeStyle/ConfigureCodeStyleOptionCodeFixProvider.cs

@@ -64,7 +64,6 @@ public Task<ImmutableArray<CodeFix>> GetFixesAsync(Project project, IEnumerable<
 
         private static ImmutableArray<CodeFix> GetConfigurations(Project project, IEnumerable<Diagnostic> diagnostics, CancellationToken cancellationToken)
         {
-            // Bail out if NativeEditorConfigSupport experiment is not enabled.
             if (!EditorConfigDocumentOptionsProviderFactory.ShouldUseNativeEditorConfigSupport(project.Solution.Workspace))
             {
                 return ImmutableArray<CodeFix>.Empty;

src/Workspaces/Core/Portable/Experiments/IExperimentationService.cs

@@ -34,7 +34,6 @@ internal static class WellKnownExperimentNames
         public const string PartialLoadMode = "Roslyn.PartialLoadMode";
         public const string TypeImportCompletion = "Roslyn.TypeImportCompletion";
         public const string TargetTypedCompletionFilter = "Roslyn.TargetTypedCompletionFilter";
-        public const string NativeEditorConfigSupport = "Roslyn.NativeEditorConfigSupport";
         public const string TriggerCompletionInArgumentLists = "Roslyn.TriggerCompletionInArgumentLists";
         public const string SQLiteInMemoryWriteCache = "Roslyn.SQLiteInMemoryWriteCache";