- `make([]a, b)` create a slice of `b` elements `a`
- `make([]a, b, c)` create a slice of `0` elements `a`, but reserve space for `c` of them
When using `append` on the former, it will result on a slice with `b` leading
elements, which is unlikely to be what we want. This commit replaces the two
instances where this happens with the latter construct.