doc-diff: force worktree add

We avoid re-creating our temporary worktree if it's already
there. But we may run into a situation where the worktree
has been deleted, but an entry still exists in
$GIT_DIR/worktrees.

Older versions of git-worktree would annoyingly create a
series of duplicate entries. Recent versions now detect and
prevent this, allowing you to override with "-f". Since we
know that the worktree in question was just our temporary
workspace, it's safe for us to always pass "-f".

Signed-off-by: Jeff King <[email protected]>
Signed-off-by: Junio C Hamano <[email protected]>

Author: peff

Documentation/doc-diff

@@ -54,7 +54,7 @@ fi
 # results that don't differ between the two trees.
 if ! test -d "$tmp/worktree"
 then
-	git worktree add --detach "$tmp/worktree" "$from" &&
+	git worktree add -f --detach "$tmp/worktree" "$from" &&
 	dots=$(echo "$tmp/worktree" | sed 's#[^/]*#..#g') &&
 	ln -s "$dots/config.mak" "$tmp/worktree/config.mak"
 fi