Merge branch 'jc/name-rev-exact-ref'

Corrects the longstanding sloppiness in the implementation of name-rev that conflated "we take commit-ish" and "differences between tags and commits do not matter". * jc/name-rev-exact-ref: describe: fix --contains when a tag is given as input name-rev: differentiate between tags and commits they point at describe: use argv-array name-rev: allow converting the exact object name at the tip of a ref name-ref: factor out name shortening logic from name_ref()