fix: refactor to save an export

src/base.ts

@@ -28,14 +28,15 @@ const context: Context = {
 
 export interface Plugins {[k: string]: [object, any, any, any, any]}
 
-export interface It<I> {
-  (expectation: string, cb?: (context: I) => any): void
-  (cb?: (context: I) => any): void
-}
-
 export type Fancy<I extends Context, T extends Plugins> = {
-  it: It<I>
-  end: It<I>
+  it: {
+    (expectation: string, cb?: (context: I) => any): void
+    (cb?: (context: I) => any): void
+  }
+  end: {
+    (expectation: string, cb?: (context: I) => any): void
+    (cb?: (context: I) => any): void
+  }
   add<K extends string, O>(key: K, cb: (context: I) => Promise<O> | O): Fancy<I & {[P in K]: O}, T>
   do(cb: (context: I) => any): Fancy<I, T>
   register<K extends string, O, A1, A2, A3, A4>(key: K, plugin: (arg1?: A1, arg2?: A2, arg3?: A3, arg4?: A4) => Plugin<O & I>): Fancy<I, T & {[P in K]: [O, A1, A2, A3, A4]}>