Relying on xref-location-marker to point to the beginning of the match
* lisp/progmodes/xref.el (xref-match-bounds): Remove.
(xref-match-length): Add.
(xref-make-match): Change the arguments.
(xref--match-buffer-bounds): Remove.
(xref-match-item): Store length, instead of end-column.
(xref-pulse-momentarily)
(xref--collect-match)
(xref--query-replace-1): Update accordingly.
(xref-query-replace): Ditto. And check that the search results
are up-to-date.