chore(rln): infallible conversions

[rymnc]

No description provided.

[github-actions]

Benchmark for 7ea10be

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Test	Base	PR	%
Pmtree::compute_root	0.0±0.00ns	0.0±0.00ns	NaN%
Pmtree::get	337.4±6.13ns	337.1±4.96ns	-0.09%
Pmtree::override_range	239.8±4.03µs	238.9±3.81µs	-0.38%
Pmtree::set	56.4±0.65µs	56.3±0.48µs	-0.18%
Pmtree:delete	56.4±0.56µs	56.5±1.35µs	+0.18%

[github-actions]

Benchmark for 7ea10be

Click to view benchmark

Test	Base	PR	%
FullMerkleTree::compute_root	0.0±0.00ns	0.0±0.00ns	NaN%
FullMerkleTree::delete	889.2±15.33ns	887.6±12.76ns	-0.18%
FullMerkleTree::get	3.5±0.07ns	3.4±0.08ns	-2.86%
FullMerkleTree::override_range	2.2±0.10µs	2.2±0.03µs	0.00%
FullMerkleTree::set	892.4±8.86ns	882.3±12.40ns	-1.13%
OptimalMerkleTree::compute_root	1050.6±16.15ns	1033.7±15.74ns	-1.61%
OptimalMerkleTree::delete	1029.6±10.38ns	1032.3±9.07ns	+0.26%
OptimalMerkleTree::get	23.0±0.32ns	22.3±0.34ns	-3.04%
OptimalMerkleTree::override_range	5.2±0.06µs	5.3±0.08µs	+1.92%
OptimalMerkleTree::set	1073.6±184.15ns	1033.2±18.76ns	-3.76%