docs: def convert_text_to_varname(text):
      r"""
      Args:
          text (str): text that might not be a valid variablename
  
      Returns:
          str: varname
  
      CommandLine:
          python -m utool.util_regex --test-convert_text_to_varname
  
      Example:
          >>> # DISABLE_DOCTEST
          >>> from utool.util_regex import *  # NOQA
          >>> text = '0) View Application-Files Directory. '
          >>> varname = convert_text_to_varname(text)
          >>> result = ('varname = %s' % (str(varname),))
          >>> print(result)
          _0_View_ApplicationFiles_Directory_
      """
      varname_pattern = '[^a-zA-Z0-9_]'
      varname = text
      # Convert spaces to underscores
      varname = varname.replace(' ', '_')
      # Remove all other non-varname chars
      varname = re.sub(varname_pattern, '', varname)
      # Make sure there are not leading numbers
      if re.match('^[0-9]', varname):
          varname = '_' + varname
      assert re.match(REGEX_VARNAME, varname), 'invalid varname=%r' % (varname,)
      return varname