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
""" Helper method to walk an etree document representing
        a QWeb template, and call ``callback(term)`` for each
        translatable term that is found in the document.
        :param etree._Element element: root of etree document to extract terms from
        :param Callable callback: a callable in the form ``f(term, source_line)``,
                                  that will be called for each extracted term.
    """
    
    
    for el in element:
        if isinstance(el, SKIPPED_ELEMENT_TYPES): continue
        if (el.tag.lower() not in SKIPPED_ELEMENTS
                and "t-js" not in el.attrib
                and not ("t-jquery" in el.attrib and "t-operation" not in el.attrib)
                and el.get("t-translation", '').strip() != "off"):
            _push(callback, el.text, el.sourceline)
            for att in ('title', 'alt', 'label', 'placeholder'):
                if att in el.attrib:
                    _push(callback, el.attrib[att], el.sourceline)
            _extract_translatable_qweb_terms(el, callback)
        _push(callback, el.tail, el.sourceline)
def babel_extract_qweb(fileobj, keywords, comment_tags, options):