Improve size adjustment of itemlist editor

Currently multi-line file names in dolphin only display a single
line when renaming. This commit ensures multi-line filenames have
all lines displayed by calling `document()->adjustSize` in
`KItemListRoleEditor::autoAdjustSize`, and by calling the latter
function after setting up the editor.

BUG: 452587

src/kitemviews/kstandarditemlistwidget.cpp

@@ -821,6 +821,7 @@ void KStandardItemListWidget::editedRoleChanged(const QByteArray &current, const
         rect.setWidth(parent->width() - rect.left());
     }
     m_roleEditor->setGeometry(rect.toRect());
+    m_roleEditor->autoAdjustSize();
     m_roleEditor->show();
     m_roleEditor->setFocus();
 }

src/kitemviews/private/kitemlistroleeditor.cpp

@@ -139,6 +139,7 @@ void KItemListRoleEditor::autoAdjustSize()
 {
     const qreal frameBorder = 2 * frameWidth();
 
+    document()->adjustSize();
     const qreal requiredWidth = document()->size().width();
     const qreal availableWidth = size().width() - frameBorder;
     if (requiredWidth > availableWidth) {

src/kitemviews/private/kitemlistroleeditor.h

@@ -51,17 +51,17 @@ Q_SIGNALS:
     void roleEditingFinished(const QByteArray &role, const QVariant &value);
     void roleEditingCanceled(const QByteArray &role, const QVariant &value);
 
-protected:
-    bool event(QEvent *event) override;
-    void keyPressEvent(QKeyEvent *event) override;
-
-private Q_SLOTS:
+public Q_SLOTS:
     /**
      * Increases the size of the editor in case if there is not
      * enough room for the text.
      */
     void autoAdjustSize();
 
+protected:
+    bool event(QEvent *event) override;
+    void keyPressEvent(QKeyEvent *event) override;
+
 private:
     /**
      * Emits the signal roleEditingFinished if m_blockFinishedSignal