Follow-up to r1637184.

* subversion/libsvn_fs_fs/fs_fs.c
  (read_format): Update docstring.

* subversion/libsvn_fs_fs/structure
  (Layout of the FS directory): Do not mention 'transactions-la' directory.
  (Filesystem format options): Update adressing mode format options.

* subversion/libsvn_fs_fs/transaction.c
  (store_l2p_index_entry): Update docstring.


git-svn-id: https://svn.apache.org/repos/asf/subversion/trunk@1637330 13f79535-47bb-0310-9956-ffa450edef68