It is trivial if
Yes, it was very stupid of me to miss that.
I dunno.
An obvious alternative is to add T next to all occurrences of M in the
table where we say "M is possible", but unless it is accompanied by an
explanation "T is just a special case of M", I suspect the resulting
description would be harder to understand than currently is, and as long
as the reader understands "T is just a special case of M", then there
isn't much point adding T everywhere M appears in the table anyway, so...
If you are suggesting that the patch you gave is preferable to actually
including T in the table, then I agree. Your patch is also better than
what I sent because it includes the unusual word "filetype", which the
user is likely to search for after seeing it in the git-status output.