(find-tag-marker-ring-length): New variable.

(find-tag-marker-ring-length): New variable.
(find-tag-marker-ring): New variable.
(tags-location-ring): New variable replacing tags-location-ring.
(tags-location-stack): Deleted.
(tags-table-format-hooks): Doc fix.
(initialize-new-tags-table): Init find-tag-marker-ring,
tags-location-ring.
(tags-reset-tags-tables): Doc fix.  Set tags-location-ring,
find-tag-marker-ring.
(find-tag-noselect): Doc fix.  Use tags-location-ring,
find-tag-marker-ring.
(find-tag, find-tag-other-window, find-tag-other-frame,
find-tag-regexp): Doc fix.
(pop-tag-mark): New function.
(esc-map): Bind pop-tag-mark.