doc bug: docs show config for vimdiff as a diff tool, but this does not work

[ilyagr]

If I try to follow this example from the config docs:

[ui]
diff.tool = "vimdiff"

[merge-tools.vimdiff]
diff-invocation-mode = "file-by-file"

I get:

$  jj diff --config ui.diff.tool=vimdiff -r @-
<1B>[?1000h<1B>[?1049h<1B>[?1h<1B>=<1B>[?2004h<1B>[?25l<pz4qph0000gn/T/jj-diff-w6yWqZ/left" is a directory<1B>[?1000l<1B>[?2004l<1B>[?2004h<1B>[?1000h" ============================================================================
" Netrw Directory Listing                                        (netrw v177)
"   /private/var/folders/lj/rv4h95_d0mxb9ryztzpz4qph0000gn/T/jj-diff-w6yWqZ/left"   Sorted by      name
"   Sort sequence: [\/]$,*,\(\.bak\|\~\|\.swp\|\.o\|\.info\|\.aux\|\.log\|\.dvi\"   Quick Help: <F1>:help  -:go up dir  D:delete  R:rename  s:sort-by  x:special" ==============================================================================../                                                                             ./
cli/
Vim: Warning: Output is not to a terminal
Vim: Warning: Input is not from a terminal

and everything freezes until I press ^C.

This is on darwin-arm.

(This happens with or without the "file-by-file" config)

I'm not sure whether there is a way to make it work; we probably need another example.

[ilyagr]

One option would be to switch the example to gvimdiff, which works, but should probably default to file-by-file and needs some config.

[ilyagr]

I think I'll add a gvimdiff and update the docs shortly. See the linked commit. I'm waiting on #6205 to make it a PR.