Proxyquire uses a fluent api

All of its api configuration methods return an object with the `Proxyquire` type.

proxyquire/proxyquire.d.ts

@@ -14,12 +14,12 @@ interface Proxyquire {
     noCallThru(): Proxyquire;
     callThru(): Proxyquire;
 
-    noPreserveCache(): void;
-    preserveCache(): void;
+    noPreserveCache(): Proxyquire;
+    preserveCache(): Proxyquire;
 }
 
 declare module 'proxyquire' {
 
     var p: Proxyquire;
     export = p;
-}
+}