Editor: ensure cursor is visible after handling backspace

Fixes: QTCREATORBUG-28316
Change-Id: I1e8c9229704c700ad76f6906b1a220948c819c1b
Reviewed-by: <github-actions-qt-creator@cristianadam.eu>
Reviewed-by: Orgad Shaneh <orgads@gmail.com>

src/plugins/texteditor/texteditor.cpp

@@ -2673,9 +2673,10 @@ void TextEditorWidget::keyPressEvent(QKeyEvent *e)
             if (cursor.hasSelection()) {
                 cursor.removeSelectedText();
                 setMultiTextCursor(cursor);
-                return;
-            }
+            } else {
                 d->handleBackspaceKey();
+            }
+            ensureCursorVisible();
             return;
         }
         break;