Move the desc- entity to the end of the file name.

[arokem]

See discussion in bids-standard/bids-specification#1895

[arokem]

Also, @tsalo proposes that we change desc-mean to desc-stat, which would gel more nicely with the functional derivatives BEP and @tsalo's own GLM derivatives BEP. If folks think that's agreeable, I can implement that here as well.

[tsalo]

Sorry I miscommunicated my idea. I mean stat-mean instead of desc-mean, as in BEP 012.

[arokem]

Of course - thanks for setting me straight. I am actually not sure that it entirely makes sense for the use-case shown here, because we have desc-mean in contrast to desc-merged and while stat-mean makes sense, I am not sure that stat-merged does.

[PeerHerholz]

Was the idea to only have stat- or desc- or could both be used, ie stat- for mean and desc- for merged given that the underlying data is obtained through different operations, one being a statistic while the other isn't?

Sorry if I missed something obvious.