chore: ruff rewrite dicts

[henryiii]

The built-in syntax is preferable to passing keywords to the dict constructor, which wastes a function call. Besides being more consistent and recognisable, it is also faster:

Python 3.11.1 (main, Dec 23 2022, 09:39:26) [Clang 14.0.0 (clang-1400.0.29.202)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
>>> import timeit
>>> timeit.timeit("dict(a=1, b=2)")
0.09944732999429107
>>> timeit.timeit("{'a': 1, 'b': 2}")
0.07909351703710854

This removes the ignoring of "C408".

[codecov]

Codecov Report

Merging #2183 (ba0084f) into main (a91d96b) will increase coverage by 0.04%.
The diff coverage is n/a.

Additional details and impacted files

Impacted Files	Coverage Δ
src/awkward/highlevel.py	77.04% <ø> (ø)
src/awkward/operations/ak_all.py	79.16% <ø> (ø)
src/awkward/operations/ak_any.py	79.16% <ø> (ø)
src/awkward/operations/ak_argcartesian.py	80.00% <ø> (ø)
src/awkward/operations/ak_argcombinations.py	82.35% <ø> (ø)
src/awkward/operations/ak_argmax.py	61.11% <ø> (ø)
src/awkward/operations/ak_argmin.py	61.11% <ø> (ø)
src/awkward/operations/ak_argsort.py	76.19% <ø> (ø)
src/awkward/operations/ak_broadcast_arrays.py	100.00% <ø> (ø)
src/awkward/operations/ak_cartesian.py	90.62% <ø> (ø)
... and 90 more

[jpivarski]

The dict constructor was only ever used in the entry-point from operations to their implementation functions. (See where the diffs are!)

The choice of dict constructor over built-in syntax was so that the function argument names would show up in the same color as they are in the entry-point function and the implementation function (as Python identifiers, not as strings). So there was a logic to it.

But activating C408 means that other instances of dict constructors can't accidentally slip in, in the future, and there's value in that.

I'm okay with making this change.

[henryiii]

We can deactivate it for a specific subset of files (assuming it can be matched on) if you'd prefer.

Actually, could _errors.OperationErrorContext take this as **kwargs instead? Then you remove the nesting, too.

[agoose77]

In this case, I think we'd sooner replace the need to setup the context manager entirely with a decorator. We just haven't gotten around to it yet :)