[uilib] `uilib.js` helper now honors explicit JSString (closes #4959538) Previously, if a JSString was inside a nested container (i.e. list or dict), it was handled as a string, not a verbatim js chunk (see docstring and test). So the following code:: >>> str(js.cw.pouet(1, {'callback': JSString('cw.mycallback')}) resulted in:: "cw.pouet(1, {'callback': 'cw.mycallback')})" while we expect (note the removed quotes):: "cw.pouet(1, {'callback': cw.mycallback)})" We use ``cubiweb.utils.js_dumps`` instead of ``cubicweb.utils.json_dumps`` which is aware of JSString.

import ConfigParser
try:
    undo_actions = config.cfgfile_parser.get('MAIN', 'undo-support', False)
except ConfigParser.NoOptionError:
    pass # this conf. file was probably already migrated
else:
    config.global_set_option('undo-enabled', bool(undo_actions))