Using shim for document highlights service

vsintegration/src/FSharp.Editor/DocumentHighlights/DocumentHighlightsService.fs

@@ -11,6 +11,7 @@ open Microsoft.CodeAnalysis
 open Microsoft.CodeAnalysis.DocumentHighlighting
 open Microsoft.CodeAnalysis.Host.Mef
 open Microsoft.CodeAnalysis.Text
+open Microsoft.CodeAnalysis.ExternalAccess.FSharp.DocumentHighlighting
 
 open FSharp.Compiler.SourceCodeServices
 open FSharp.Compiler.Range
@@ -20,8 +21,7 @@ type internal FSharpHighlightSpan =
       TextSpan: TextSpan }
     override this.ToString() = sprintf "%+A" this
 
-[<Shared>]
-[<ExportLanguageService(typeof<IDocumentHighlightsService>, FSharpConstants.FSharpLanguageName)>]
+[<Export(typeof<IFSharpDocumentHighlightsService>)>]
 type internal FSharpDocumentHighlightsService [<ImportingConstructor>] (checkerProvider: FSharpCheckerProvider, projectInfoManager: FSharpProjectOptionsManager) =
 
     static let userOpName = "DocumentHighlights"
@@ -72,8 +72,8 @@ type internal FSharpDocumentHighlightsService [<ImportingConstructor>] (checkerP
                 |> fixInvalidSymbolSpans sourceText symbol.Ident.idText
         }
 
-    interface IDocumentHighlightsService with
-        member __.GetDocumentHighlightsAsync(document, position, _documentsToSearch, cancellationToken) : Task<ImmutableArray<DocumentHighlights>> =
+    interface IFSharpDocumentHighlightsService with
+        member __.GetDocumentHighlightsAsync(document, position, _documentsToSearch, cancellationToken) : Task<ImmutableArray<FSharpDocumentHighlights>> =
             asyncMaybe {
                 let! parsingOptions, projectOptions = projectInfoManager.TryGetOptionsForEditingDocumentOrProject(document, cancellationToken)
                 let! sourceText = document.GetTextAsync(cancellationToken)
@@ -85,11 +85,11 @@ type internal FSharpDocumentHighlightsService [<ImportingConstructor>] (checkerP
                 let highlightSpans = 
                     spans 
                     |> Array.map (fun span ->
-                        let kind = if span.IsDefinition then HighlightSpanKind.Definition else HighlightSpanKind.Reference
-                        HighlightSpan(span.TextSpan, kind))
+                        let kind = if span.IsDefinition then FSharpHighlightSpanKind.Definition else FSharpHighlightSpanKind.Reference
+                        FSharpHighlightSpan(span.TextSpan, kind))
                     |> Seq.toImmutableArray
 
-                return ImmutableArray.Create(DocumentHighlights(document, highlightSpans))
+                return ImmutableArray.Create(FSharpDocumentHighlights(document, highlightSpans))
             }   
-            |> Async.map (Option.defaultValue ImmutableArray<DocumentHighlights>.Empty)
+            |> Async.map (Option.defaultValue ImmutableArray<FSharpDocumentHighlights>.Empty)
             |> RoslynHelpers.StartAsyncAsTask(cancellationToken)