Utils: Remove FilePath::operator+()

This was a alias for .stringAppended(), but can be used too easily
when .pathAppended() is meant.

Change-Id: Ia3b64d39828d4074b43d87c923ce3a6a87038948
Reviewed-by: Christian Stenger <christian.stenger@qt.io>
Reviewed-by: <github-actions-qt-creator@cristianadam.eu>

src/libs/utils/stringutils.cpp

@@ -482,4 +482,14 @@ QTCREATOR_UTILS_EXPORT QStringView chopIfEndsWith(QStringView str, QChar c)
     return str;
 }
 
+QTCREATOR_UTILS_EXPORT QString appendHelper(const QString &base, int n)
+{
+    return base + QString::number(n);
+}
+
+QTCREATOR_UTILS_EXPORT FilePath appendHelper(const FilePath &base, int n)
+{
+    return base.stringAppended(QString::number(n));
+}
+
 } // namespace Utils