doT.js API allows modification of the exported templateSettings property. Change from const (#16385)

types/dot/dot-tests.ts

@@ -23,6 +23,8 @@ const data = {
 	name: "My name"
 };
 
+doT.templateSettings.varname = 'test';
+
 let pagefn = doT.template(pagetmpl, undefined, def);
 const content = pagefn(data);
 

types/dot/index.d.ts

@@ -8,8 +8,8 @@ export as namespace doT;
 /** Version number */
 export const version: string;
 
-/** Default template settings */
-export const templateSettings: TemplateSettings;
+/** Template settings */
+export let templateSettings: TemplateSettings;
 
 export type RenderFunction = (...args: any[]) => string;