Drop Formatting.jl

[nickrobinson251]

Formatting.jl is no longer recently added a rather ugly and annoying deprecation warning that makes it clear it does not want to be used.

 Formatting
│  ┌ Warning: DEPRECATION NOTICE
│  │
│  │ Formatting.jl has been unmaintained for a while, with some serious
│  │ correctness bugs compromising the original purpose of the package. As a result,
│  │ it has been deprecated - consider using an alternative, such as
│  │ `Format.jl` (https://github.com/JuliaString/Format.jl) or the `Printf` stdlib directly.
│  │
│  │ If you are not using Formatting.jl as a direct dependency, please consider
│  │ opening an issue on any packages you are using that do use it as a dependency.
│  │ From Julia 1.9 onwards, you can query `]why Formatting` to figure out which
│  │ package originally brings it in as a dependency.
│  └ @ Formatting ~/packages/Formatting/3VxOt/src/Formatting.jl:12

Here i just copy-pasted in the one feature of it that seems to be used https://github.com/JuliaIO/Formatting.jl/blob/0db1b043dfe6f0a2678cb48813b49565c2ef89f9/src/cformat.jl#L77-L93
The function could be more efficient, but i just wanted to do the most like-for-like change in this PR.

an alternative would be to switch to Format.jl but the dependency hardly seems worth it.

[nickrobinson251]

cc @NHDaly do you have merge rights here? can you review please?

[carstenbauer]

Thanks for taking care of this. My comments are only minor. If you say that you don't want to / don't have time to address them I would be fine with merging as is.