Update test traits to support `f16` and `f128`, as applicable. Add the
new routines (`fabs` and `copysign` for `f16` and `f128`) to the list of
all operations.
Now that we are using rustdoc output to locate public functions, the
test is indicating a few that were missed since they don't have their
own function. Update everything to now include the following routines:
* `erfc`
* `erfcf`
* `y0`
* `y0f`
* `y1`
* `y1f`
* `yn`
* `ynf`
This will enable us to `include!` the file to access these types in
`libm-test`, rather than somehow reproducing the types as part of the
macro. Ideally `libm-test` would just `use` the types from `libm-macros`
but proc macro crates cannot currently export anything else.
This also adjusts naming to closer match the scheme described in
`libm_test::op`.
