MPV: Try to fix MPV close problems by using the mpv_terminate_destroy call

src/UI/DocumentViews/MpvContainer.cc

@@ -69,7 +69,7 @@ MpvContainer::closeMpv() noexcept
         registerMpvDurationCallback(nullptr);
         mpv_handle *tmp_mpv = mpv;
         mpv                 = nullptr; // Stop all other callbacks here
-        mpv_destroy(tmp_mpv);
+        mpv_terminate_destroy(tmp_mpv);
     }
 }
 
@@ -239,6 +239,10 @@ MpvContainer::onMpvEvent() noexcept
             break;
         handleMpvEvent(event);
     }
+
+    if (mpv == nullptr) {
+        qDebug() << "MPV was closed while in the event loop!";
+    }
 }
 
 void