Change more things.

Things changed:
 - make getImageFileFormat case insensitive
 - use QTextEdit::dragEnterEvent instead of QAbstractScrollArea::dragEnterEvent,
 - Make dragEnterEvent() and dropEvent() overrides.

src/util/NuulsUploader.cpp

@@ -16,7 +16,7 @@ QString getImageFileFormat(QString path)
     static QStringList listOfImageFormats = {".png", ".jpg", ".jpeg"};
     for (const QString &format : listOfImageFormats)
     {
-        if (path.endsWith(format))
+        if (path.endsWith(format, Qt::CaseInsensitive))
         {
             return format.mid(1);
         }

src/widgets/helper/ResizingTextEdit.cpp

@@ -291,7 +291,7 @@ void ResizingTextEdit::dragEnterEvent(QDragEnterEvent *event)
     }
     else
     {
-        QAbstractScrollArea::dragEnterEvent(event);
+        QTextEdit::dragEnterEvent(event);
     }
 }
 

src/widgets/helper/ResizingTextEdit.hpp

@@ -34,8 +34,8 @@ protected:
     bool canInsertFromMimeData(const QMimeData *source) const override;
     void insertFromMimeData(const QMimeData *source) override;
 
-    void dragEnterEvent(QDragEnterEvent *event);
-    void dropEvent(QDropEvent *event);
+    void dragEnterEvent(QDragEnterEvent *event) override;
+    void dropEvent(QDropEvent *event) override;
 
 private:
     // hadSpace is set to true in case the "textUnderCursor" word was after a