Remove some docstring ambiguity, and leave a comment with a suggestion
for a possible future change of behavior.

* subversion/include/svn_repos.h
  (svn_repos_load_fs4, svn_repos_get_fs_build_parser4): Remove @note
    about what might happen when filtering by revision range.  Current
    behavior exactly matches the most naive interpretation of the
    remaining docstrings anyway.

* subversion/libsvn_repos/load-fs-vtable.c
  (new_revision_record): Leave a comment about a different way we
    could handle out-of-range revisions.


git-svn-id: https://svn.apache.org/repos/asf/subversion/trunk@1463213 13f79535-47bb-0310-9956-ffa450edef68