title: PaginatedDataTable change "Rows per page" String
body: <p>I am using PaginatedDataTable in my app and I got it working perfectly. But I want to change the String of "Rows per page" which is shown in the image bellow. I want to change it to something like "MY Rows" or "Rows in a page" or ... .
  <a href="https://i.stack.imgur.com/GSoFB.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/GSoFB.png" alt="enter image description here"></a></p>
  
  <pre class="lang-dart prettyprint-override"><code>PaginatedDataTable(
    header: Text(widget.chartsInfo.title),
    rowsPerPage: _rowsPerPage,
    availableRowsPerPage: [5, 10, 15],
    columnSpacing: 15,
    onRowsPerPageChanged: (int value) {
      setState(() {
        _rowsPerPage = value;
      });
     },
     sortColumnIndex: _sortColumnIndex,
     sortAscending: _sortAscending,
     onSelectAll: _resultsDataSource._selectAll,
     columns: dataColumns,
     source: _resultsDataSource),```
  </code></pre>