Merge branch 'kj/repo-info-more-path-keys' into seen

Merge branch 'kj/repo-info-more-path-keys' into seen

The 'git repo info' command has been taught more keys to output
paths of various repository components (such as the working tree
root, superproject working tree, object database, etc.), supporting
both absolute and relative path formats.

* kj/repo-info-more-path-keys:
  repo: add path.git-prefix path key
  repo: add path.grafts with absolute and relative suffix formatting
  repo: add path.index with absolute and relative suffix formatting
  repo: add path.hooks with absolute and relative suffix formatting
  repo: add path.objects with absolute and relative suffix formatting
  repo: add path.superproject-working-tree with absolute and relative suffixes
  repo: add path.toplevel with absolute and relative suffix formatting