We keep __fish_is_nth_token for compatibility and edit the
implementations of __fish_is_nth_token, __fish_is_first_token and
__fish_is_token_n to use fish_is_nth_token
It seems that under python3, s3cmd emits its output as a long list (like
ls -l) with or without the --long parameter to "s3cmd ls s3://...".
This patch includes only s3://* paths from that output as completions.
Per the discussion with @faho in #4332, replaced some custom completion
state detection functions with standard __fish_* functions used in other
completion sources.
(cherry picked from commit f706081ea4)
No longer auto-generated. Everything has been summarized. Supressing
file completions for initial command, providing list of valid initial
commands, filtering --options by subcommand.
(cherry picked from commit 539acd9fc5)
