Fix markdown preview not closing after chaning settings

Fixes #32009

src/vs/workbench/parts/html/browser/htmlPreviewPart.ts

@@ -178,7 +178,7 @@ export class HtmlPreviewPart extends WebviewEditor {
 
 	public setInput(input: EditorInput, options?: EditorOptions): TPromise<void> {
 
-		if (this.input && this.input.matches(input) && this._hasValidModel()) {
+		if (this.input && this.input.matches(input) && this._hasValidModel() && this.input instanceof HtmlInput && input instanceof HtmlInput && areHtmlInputOptionsEqual(this.input.options, input.options)) {
 			return TPromise.as(undefined);
 		}
 

src/vs/workbench/parts/html/common/htmlInput.ts

@@ -29,12 +29,4 @@ export class HtmlInput extends ResourceEditorInput {
 	) {
 		super(name, description, resource, textModelResolverService);
 	}
-
-	public matches(otherInput: any): boolean {
-		if (!super.matches(otherInput)) {
-			return false;
-		}
-
-		return otherInput instanceof HtmlInput && areHtmlInputOptionsEqual(this.options, otherInput.options);
-	}
 }