* gcc_release (announce_snapshot): Add substitution of @BRANCH
for README and index.html. Remove substitution of @LONG_DATE.
Put index.html into the respective snapshot directory.
Adjust subject of the notification mail to the new naming scheme
for CVS tags.
Adjust name of the LATEST-IS-... files to the new naming scheme
for snapshot directories.
(FTP_PATH): Ditto.
(LAST_DIR): Ditto.
(LAST_LONG_DATE): Remove.
* snapshot-README: Adjust to the new naming schemes for directories
and snapshots per se.
Dynamically fill in the respective branch instead of hardcoding it.
* snapshot-index.html: Replace individual links to diffs with a
general link to the diff/ subdirectory.
Mention the concrete snapshot in <title> and <h1>.
Adjust links to the new location of index.html.
git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@69143 138bc75d-0d04-0410-961f-82ee72b054a4