View/session files for buftype=acwrite buffers don't store fold information

[James McCoy]

put_view() only stores the fold information if "bt_normal() ||
bt_help()" is true. Since bt_normal() excludes any buffers where
'buftype' is set, this prevents fold info being stored for
buftype=acwrite.

I think storing the folds would make sense for this type of buffer.
This also makes me wonder whether the other uses of bt_normal() should
be reviewed to see if more of them should also apply to buftype=acwrite.

Cheers,
--
James
GPG Key: 4096R/91BF BF4D 6956 BD5D F7B7 2D23 DFE6 91AE 331B A3DB