enable non-latin variable descriptions in CodeFileEditor

fix following backtrace:

UnicodeEncodeError: 'ascii' codec can't encode characters in position 0-7: ordinal not in range(128)
Traceback (most recent call last):
File "beremiz/editors/CodeFileEditor.py", line 610, in GetValue
return str(self.data[row].get(self.GetColLabelValue(col, False), ""))
UnicodeEncodeError: 'ascii' codec can't encode characters in position 0-7: ordinal not in range(128)

     1

<?xml version='1.0' encoding='utf-8'?>

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<BeremizRoot xmlns:xsd="http://www.w3.org/2001/XMLSchema" URI_location="LOCAL://">

     3

  <TargetType/>

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</BeremizRoot>