Additional conversions for Unitful

[MilesCranmer]

No description provided.

[github-actions]

Benchmark Results

	main	807b31c...	t[main]/t[807b31c...]
creation/Quantity(x)	13.7 ± 0.1 ns	4.8 ± 0.4 ns	2.85
creation/Quantity(x, length=y)	5.2 ± 0.4 ns	4.9 ± 0.4 ns	1.06
time_to_load	0.162 ± 0.0053 s	0.161 ± 0.0068 s	1
with_numbers/*real	4 ± 0.3 ns	4.1 ± 0.1 ns	0.976
with_numbers/^int	0.0327 ± 0.004 μs	0.0326 ± 0.004 μs	1
with_numbers/^int * real	0.0334 ± 0.0037 μs	0.033 ± 0.0036 μs	1.01
with_quantity//y	24.5 ± 0.8 ns	23.4 ± 1.8 ns	1.05
with_quantity/^y	1.51 ± 0.3 μs	1.57 ± 0.32 μs	0.963
with_self/dimension	1.9 ± 0.1 ns	2 ± 0.2 ns	0.95
with_self/inv	20.5 ± 1.6 ns	22.1 ± 1.6 ns	0.928
with_self/ustrip	1.9 ± 0.1 ns	2 ± 0.2 ns	0.95

Benchmark Plots

A plot of the benchmark results have been uploaded as an artifact to the workflow run for this PR.
Go to "Actions"->"Benchmark a pull request"->[the most recent run]->"Artifacts" (at the bottom).