`Matchit` malfunctions under specific conditions.

[gen740]

Steps to reproduce

• Create the following file minimal.vim

  call setline(1, ["a(", "any text", ")"])
  normal f(
  call feedkeys("v%")

• nvim --clean -u minimal.vim

Expected behavior

Selected the region enclosed by ().

[chrisbra]

Hm, it runs into this condition here, which breaks it:

https://github.com/chrisbra/matchit/blob/5428ebbc670ef3c73c74a94faad109d76a091e66/plugin/matchit.vim#L53

I have no idea why this was added initially.

If you use this mapping:

xnoremap <silent> <Plug>(MatchitVisualForward)     :<C-U>call matchit#Match_wrapper('',1,'v')<CR>m'gv``

it seems to work. But it probably breaks at another place then.