[mathjax] add menuSettings.renderer (#39005)

* Narrower typing for getOption and setOption

* Add "div" to CoordsMode (not documented in manual, but present in source code)

* Move catchall on/off below ones with explicit names so that handler arguments get correct typing

* Narrow type of event parameter for DOMEvent handler

* Fix string type accidentally left unnarrowed

* Added menuSettings.renderer

types/mathjax/index.d.ts

@@ -552,6 +552,8 @@ declare namespace MathJax {
 
         mpContext?: boolean;
         mpMouse?: boolean;
+
+        readonly renderer?: "HTML-CSS" | "CommonHTML" | "PreviewHTML" | "NativeMML" | "SVG" | "PlainSource";
     }
 
     export interface ErrorSettings {