Fix big endian bit_order lsb writing

[wcampbell0x2a]

• Fix writing under 8 bits when Big Endian Lsb

[github-actions]

Benchmark for e578196

Click to view benchmark

Test	Base	PR	%
count_from_u8_specialize	100.2±0.67ns	104.3±0.88ns	+4.09%
count_no_specialize	2.1±0.05µs	2.4±0.05µs	+14.29%
count_specialize	100.1±1.18ns	102.4±1.15ns	+2.30%
deku_read_bits	1257.0±17.86ns	1281.2±15.81ns	+1.93%
deku_read_byte	3.8±0.02ns	4.6±0.05ns	+21.05%
deku_read_enum	3.2±0.03ns	4.0±0.04ns	+25.00%
deku_read_vec	31.0±0.54ns	31.1±0.72ns	+0.32%
deku_write_bits	239.0±6.80ns	227.9±3.03ns	-4.64%
deku_write_byte	24.3±0.26ns	24.3±0.35ns	0.00%
deku_write_enum	23.7±0.39ns	23.7±0.34ns	0.00%
deku_write_vec	730.3±24.39ns	326.0±3.25ns	-55.36%
read_all	4.3±0.04µs	5.1±0.03µs	+18.60%
read_all_bytes	4.3±0.05µs	5.1±0.03µs	+18.60%

[sharksforarms]

thanks for your continued efforts @wcampbell0x2a. Time to cut a release you think?