add static method example

examples/napi/__test__/typegen.spec.ts.md

@@ -33,6 +33,7 @@ Generated by [AVA](https://avajs.dev).
       get name(): string␊
       set name(name: string)␊
       whoami(): string␊
+      static getDogKind(): Kind␊
     }␊
     export class PackageJson {␊
       name: string␊

examples/napi/index.d.ts

@@ -23,6 +23,7 @@ export class Animal {
   get name(): string
   set name(name: string)
   whoami(): string
+  static getDogKind(): Kind
 }
 export class PackageJson {
   name: string

examples/napi/src/class.rs

@@ -41,6 +41,11 @@ impl Animal {
       Kind::Duck => format!("Duck: {}", self.name),
     }
   }
+
+  #[napi]
+  pub fn get_dog_kind() -> Kind {
+    Kind::Dog
+  }
 }
 
 #[napi(constructor)]