Add docs to the getPin Method

src/main/java/com/cringe_studios/cringe_authenticator_library/OTP.java

@@ -54,6 +54,11 @@ public abstract class OTP {
 	
 	public abstract long getNextDueTime();
 	
+	/**
+	 * 
+	 * @return s the current ping, as calculated by the counter or the current time, unless it
+	 * @throws an OTPException
+	 */
 	public abstract String getPin() throws OTPException;
 	
 	public abstract void incrementCounter();