chore: typings fix

Author: farfromrefug

src/index.d.ts

@@ -1,12 +1,11 @@
 export declare class TNSTextToSpeech {
+    init(): Promise<void>;
 
-    async init();
-    
     /**
      * Initiate the text to speech.
      * @param {object} SpeakOptions - SpeakOptions object.
      */
-    async speak(options: SpeakOptions);
+    speak(options: SpeakOptions): Promise<void>;
 
     /**
      * Release the resources used by the TextToSpeech engine/synthesizer

src/texttospeech.ios.ts

@@ -45,7 +45,7 @@ export class TNSTextToSpeech {
     delegate: MySpeechDelegate;
 
     public async init() {
-      //stub function to be like android
+        //stub function to be like android
     }
     public async speak(options: SpeakOptions): Promise<any> {
         if (!this._speechSynthesizer) {