Search also on source for some translation types when overriding

issue3637
review3221004
(transplanted from 6721c1f1bc0cddbdc6707b4c9803c6d56f6b459d)

--HG--
extra : transplant_source : g%21%C1%F1%BC%0C%DD%BD%C6p%7BL%98%03%C6%D5okE%9D