In addition to purely abbreviated commit object names, "gitweb"
learned to turn "git describe" output (e.g. v2.9.3-599-g2376d31787)
into clickable links in its output.
* ab/gitweb-abbrev-links:
gitweb: link to "git describe"'d commits in log messages
gitweb: link to 7-char+ SHA-1s, not only 8-char+
gitweb: fix a typo in a comment