Update tools/text_processing/text_processing/recurring_lines.xml

Co-authored-by: Marius van den Beek <m.vandenbeek@gmail.com>

Author: pavanvidem

tools/text_processing/text_processing/recurring_lines.xml

@@ -22,7 +22,7 @@
         <repeat name="token_set" title=" selection" min="1">
             <param name="line" type="text"
                 label="Characters to insert" help="Specify the characters that will be inserted X times in every line">
-                    <sanitizer invalid_char="">
+                    <sanitizer>
                         <valid initial="default">
                             <add value="&#9;" />  <!-- &#9; is the HTML entity for a tab -->
                         </valid>