Merge from vscode 4636be2b71c87bfb0bfe3c94278b447a5efcc1f1 (#8722)

* Merge from vscode 4636be2b71c87bfb0bfe3c94278b447a5efcc1f1

* remove tests that aren't working

src/vs/base/common/async.ts

@@ -34,7 +34,7 @@ export function createCancelablePromise<T>(callback: (token: CancellationToken)
 		});
 	});
 
-	return new class implements CancelablePromise<T> {
+	return <CancelablePromise<T>>new class {
 		cancel() {
 			source.cancel();
 		}

src/vs/base/common/htmlContent.ts

@@ -5,7 +5,7 @@
 
 import { equals } from 'vs/base/common/arrays';
 import { UriComponents } from 'vs/base/common/uri';
-import { escapeCodicons, markdownUnescapeCodicons } from 'vs/base/common/codicons';
+import { escapeCodicons } from 'vs/base/common/codicons';
 
 export interface IMarkdownString {
 	readonly value: string;
@@ -39,10 +39,9 @@ export class MarkdownString implements IMarkdownString {
 
 	appendText(value: string): MarkdownString {
 		// escape markdown syntax tokens: http://daringfireball.net/projects/markdown/syntax#backslash
-		value = value
+		this._value += (this._supportThemeIcons ? escapeCodicons(value) : value)
 			.replace(/[\\`*_{}[\]()#+\-.!]/g, '\\$&')
 			.replace('\n', '\n\n');
-		this._value += this.supportThemeIcons ? markdownUnescapeCodicons(value) : value;
 
 		return this;
 	}
@@ -61,10 +60,6 @@ export class MarkdownString implements IMarkdownString {
 		this._value += '\n```\n';
 		return this;
 	}
-
-	static escapeThemeIcons(value: string): string {
-		return escapeCodicons(value);
-	}
 }
 
 export function isEmptyMarkdownString(oneOrMany: IMarkdownString | IMarkdownString[] | null | undefined): boolean {

src/vs/base/common/map.ts

@@ -526,6 +526,14 @@ export class LinkedMap<K, V> {
 		return this._size;
 	}
 
+	get first(): V | undefined {
+		return this._head?.value;
+	}
+
+	get last(): V | undefined {
+		return this._tail?.value;
+	}
+
 	has(key: K): boolean {
 		return this._map.has(key);
 	}