Tags: patch

Hello Dmitry, All,

This patch adds support for bookmarking "*xref*" buffers and restoring
them later, even across Emacs sessions.

To make this happen, we need to propagate some more information to the
"*xref*" buffer (and any other Xref fronted).  We do this, without
breaking compatibility, by setting a new variable from inside the xrefs
fetcher function.  The frontend can examine this variable to learn all
about the source of the fetched xrefs after invoking the fetcher.
Namely, the "*xref*" buffer uses this information to create bookmarks.

WDYT?