Fix starting scroll for URIs with fragment (microsoft#111126)

Author: dsanders11

extensions/markdown-language-features/src/features/preview.ts

@@ -91,7 +91,7 @@ class StartingScrollLine {
 	) { }
 }
 
-class StartingScrollFragment {
+export class StartingScrollFragment {
 	public readonly type = 'fragment';
 
 	constructor(

extensions/markdown-language-features/src/features/previewContentProvider.ts

@@ -65,6 +65,7 @@ export class MarkdownContentProvider {
 		const config = previewConfigurations.loadAndCacheConfiguration(sourceUri);
 		const initialData = {
 			source: sourceUri.toString(),
+			fragment: state?.fragment || markdownDocument.uri.fragment || undefined,
 			line: initialLine,
 			lineCount: markdownDocument.lineCount,
 			scrollPreviewWithEditor: config.scrollPreviewWithEditor,

extensions/markdown-language-features/src/features/previewManager.ts

@@ -9,7 +9,7 @@ import { MarkdownEngine } from '../markdownEngine';
 import { MarkdownContributionProvider } from '../markdownExtensions';
 import { Disposable, disposeAll } from '../util/dispose';
 import { TopmostLineMonitor } from '../util/topmostLineMonitor';
-import { DynamicMarkdownPreview, ManagedMarkdownPreview, StaticMarkdownPreview } from './preview';
+import { DynamicMarkdownPreview, ManagedMarkdownPreview, StartingScrollFragment, StaticMarkdownPreview } from './preview';
 import { MarkdownPreviewConfigurationManager } from './previewConfig';
 import { MarkdownContentProvider } from './previewContentProvider';
 
@@ -106,7 +106,10 @@ export class MarkdownPreviewManager extends Disposable implements vscode.Webview
 			preview = this.createNewDynamicPreview(resource, settings);
 		}
 
-		preview.update(resource);
+		preview.update(
+			resource,
+			resource.fragment ? new StartingScrollFragment(resource.fragment) : undefined
+		);
 	}
 
 	public get activePreviewResource() {