`^{}` config names are often too long

[spencertipping]

A common case is for sort optimization: ^{row/sort-buffer=65536m row/sort-compress=lz4} g is pretty ridiculous. Another one is for S, which is less bad but still not great: ^{scale/ibuf=64 scale/obuf=64} S8[...].

Some options:

1. Define short aliases for config options (meh)
2. Expand the g and S grammars to handle insta-configs as arguments
3. Prepend fast configs onto operators: ni ... %o6g (o = lzo, 6 = 1024 << 6 MB buffer) -- if we do this, we need to make sure we don't collide with reasonable uses of % interleave