fix: add escape to CSS

Closes:
microsoft/TypeScript#21090

Author: alan-agius4

baselines/dom.generated.d.ts

@@ -1819,9 +1819,12 @@ declare var CryptoKeyPair: {
 };
 
 interface CSS {
-    supports(property: string, value?: string): boolean;
+    escape(value: string): string;
 }
-declare var CSS: CSS;
+
+declare var CSS: {
+    supports(property: string, value?: string): boolean;
+};
 
 interface CSSConditionRule extends CSSGroupingRule {
     conditionText: string;

inputfiles/addedTypes.json

@@ -2980,5 +2980,13 @@
         "signatures": [
             "animate(keyframes: AnimationKeyFrame | AnimationKeyFrame[], options: number | AnimationOptions): Animation"
         ]
+    },
+    {
+        "kind": "method",
+        "name": "escape",
+        "interface": "CSS",
+        "signatures": [
+            "escape(value: string): string"
+        ]
     }
 ]