worktree: use 'worktree' over 'working tree'
It is helpful to distinguish between a 'working tree' and a 'worktree'.
A worktree contains a working tree plus additional metadata. This
metadata includes per-worktree refs and worktree-specific config.
This is the last of multiple changes to git-worktree.txt, starting at
the LIST OUTPUT FORMAT section.
The EXAMPLES section has an instance of "working tree" that must stay as
it is, because it is not talking about a worktree, but an example of why
a user might want to create a worktree.
Helped-by: Taylor Blau <me@ttaylorr.com>
Signed-off-by: Derrick Stolee <derrickstolee@github.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>