move html out of index, add class Raw and document

mw/html.d.ts

@@ -0,0 +1,36 @@
+declare global {
+    namespace mw {
+        namespace html {
+            /**
+             * Escape a string for HTML.
+             * Converts special characters to HTML entities.
+             * @param {string} s The string to escape
+             * @returns {string} HTML
+             */
+            function escape(s: string): string;
+
+            /**
+             * Create an HTML element string, with safe escaping.
+             * @param {string} name The tag name
+             * @param {{ [key: string]: string }} attrs An object with members mapping element names to values
+             * @param {string | html.Raw} contents The contents of the element
+             * @returns {string} HTML
+             */
+            function element(
+                name: string,
+                attrs?: Record<string, string>,
+                contents?: string | mw.html.Raw
+            ): string;
+
+            /**
+             * Wrapper object for raw HTML passed to mw.html.element().
+             */
+            class Raw<V extends string = string> {
+                constructor(value: V);
+                private value: V;
+            }
+        }
+    }
+}
+
+export {};

mw/index.d.ts

@@ -84,12 +84,6 @@ declare global {
             wgWikibaseItemId: string;
         }>;
 
-        namespace html {
-            function escape(s: string): string;
-
-            function element(name: string, attrs?: any, contents?: string): string;
-        }
-
         namespace log {
             function deprecate(
                 obj: any,