Improve precision and gas costs in_shareMochi

[code423n4]

Handle

pauliax

Vulnerability details

Impact

This not only loses some precision (cuz of multiplication and division) but also consumes more gas:
// send Mochi to vMochi Vault
mochi.transfer(
address(engine.vMochi()),
(mochiBalance * vMochiRatio) / 1e18
);
// send Mochi to veCRV Holders
mochi.transfer(
crvVoterRewardPool,
(mochiBalance * (1e18 - vMochiRatio)) / 1e18
);

Recommended Mitigation Steps

Proposed improvement:
// send Mochi to vMochi Vault
uint toVault = (mochiBalance * vMochiRatio) / 1e18;
mochi.transfer(
address(engine.vMochi()),
toVault
);
// send Mochi to veCRV Holders
mochi.transfer(
crvVoterRewardPool,
mochiBalance - toVault;
);

This way you the whole mochiBalance will be transferred and it will cost less to do that as fewer math operations are performed.