Remove BitBuffer::into_mut and require callers to handle failure to acquire unique ownership

[robert3005]

BitBuffer::into_mut is an escape hatch that will make the callers copy the whole
buffer while they can implement better logic by fusing their buffer operation
with the copy

Signed-off-by: Robert Kruszewski github@robertk.io

[codspeed-hq]

Merging this PR will improve performance by 11.88%

⚡ 2 improved benchmarks
✅ 1014 untouched benchmarks
⏩ 1522 skipped benchmarks¹

Performance Changes

	Mode	Benchmark	BASE	HEAD	Efficiency
⚡	Simulation	bitwise_not_vortex_buffer[1024]	4.5 µs	4 µs	+11.88%
⚡	Simulation	bitwise_not_vortex_buffer[2048]	4.6 µs	4.2 µs	+10.07%

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_{Comparing rk/bitbufferintomut (c960faf) with develop (f03a0c7)}

Footnotes

1. 1522 benchmarks were skipped, so the baseline results were used instead. If they were deleted from the codebase, click here and archive them to remove them from the performance reports. ↩