rust-index: avoid some cloning in find_gca_candidates()
Instead of keeping the information whether the current revision is
poisoned on `current_seen`, we extract it as a boolean.
This also allows us to simplify the explanation of `seen[r].is_poisoned()`,
as the exceptional case where it is poisoned right after `r` has been
determined to be a solution does no longer exist.
# Declare Windows-specific requirements for generating
# the compiled (frozen) set of requirements in
# ./requirements-windows-py3.txt.
# If run on Windows, it may be necessary to run dos2unix
# on the output file to replace any CRLF newlines with LF.
docutils
dulwich
# Needed by the release note tooling
fuzzywuzzy
keyring
pygit2
pygments
# Needed by the phabricator tests
pytest-vcr
# Need to list explicitly so dependency gets pulled in when
# not running on Windows.
pywin32-ctypes
windows-curses