Impacted versions:
Master branch, should by 12.0

Steps to reproduce:
Install a third party addon with localization po file in i18n folder, even loading translation manually, the translation won't work, The console reports error: Translation .... not found in reference pot, skipping.
Reverse the change of  "odoo/tools/translate.py" in this commit, the issue was gone.

Expected behavior:
The po translation works as before.



odoo/tools/translate.py
return etree.fromstring(text)
def serialize_xml(node):
    return etree.tostring(node, method='xml', encoding='unicode')
_HTML_PARSER = etree.HTMLParser(encoding='utf8')
def parse_html(text):
    return html.fragment_fromstring(text, parser=_HTML_PARSER)
def serialize_html(node):
    return etree.tostring(node, method='html', encoding='unicode')
def xml_translate(callback, value):
    """ Translate an XML value (string), using `callback` for translating text
        appearing in `value`.
    """
    if not value:
        return value
    try:
        root = parse_xml(value)
        result = translate_xml_node(root, callback, parse_xml, serialize_xml)
        return serialize_xml(result)
    except etree.ParseError:
        
        root = parse_html(u"<div>%s</div>" % value)
        result = translate_xml_node(root, callback, parse_xml, serialize_xml)
        
        return serialize_xml(result)[5:-6]
def html_translate(callback, value):