Fix drop for VoskSession and made get_final_result consume the session

src/model.rs

@@ -42,7 +42,7 @@ impl VoskModel {
     }
 
     #[inline]
-    pub fn get_final_result(&self, sess: &mut VoskSession) -> crate::TranscriptionResult {
+    pub fn get_final_result(&self, sess: VoskSession) -> crate::TranscriptionResult {
         let cstr = unsafe { CStr::from_ptr(ffi::vosk_recognizer_final_result(sess.inner)) };
 
         serde_json::from_str(cstr.to_str().unwrap()).unwrap()

src/session.rs

@@ -101,3 +101,9 @@ impl VoskSession {
         }
     }
 }
+
+impl Drop for VoskSession {
+    fn drop(&mut self) {
+        unsafe { ffi::vosk_recognizer_free(self.inner) }
+    }
+}