Small fixes

[bbenligiray]

A bunch of small fixes:

• In Api3Voting, EPOCH_LENGTH is already assigned to voteTime in initialize() and since EPOCH_LENGTH and voteTime don't change, we can use voteTime instead of fetching EPOCH_LENGTH from the pool contract. It will just be slightly cheaper.

• Typecasts at checkpoint arrays were assert()ed but the ones at reward records weren't, so added it for the sake of completeness.

• totalStake is added to the reward records. This is actually not used in anywhere in the contract, but the problem I wanted to solve is that we don't keep any history of total staked amount on-chain for someone to build an external contract that uses that somehow. It just makes reward payments a bit more expensive so felt like it's worth it.

• Delegation and delegation update events being the same was confusing, so created another one.

• Small formatting and comment stuff

[acenolaza]

LGTM 👍🏻
Just added a few minor comments that might be useful.

[bbenligiray]

I added totalStake to the RewardMinted event as you've mentioned. Then I also added totalShares to Staked and ScheduledUnstakeas this was something recommended by Team Omega informally. Then I updated the events to log all major state variables (that change) to make it easier to index these in the future. This doesn't affect how the current dashboard works at all.

[acenolaza]

LGTM again. I was just wondering, should we add "To" to variables like userSharesUpdate (userSharesToUpdate) for consistency with other local variables (i.e. delegatedToUpdate)?

[acenolaza]

Should we also add source to the event just for completeness and consistency since we are adding all inputs on other events?

[bbenligiray]

source will always be timelockManager (which is immutable) due to the awkward way TimelockManager.sol was implemented, so not really needed (could be done for consistency but meh)

[acenolaza]

same here in this event

[bbenligiray]

source is also only timelockManager

[bbenligiray]

LGTM again. I was just wondering, should we add "To" to variables like userSharesUpdate (userSharesToUpdate) for consistency with other local variables (i.e. delegatedToUpdate)?

delegatedToUpdate is called that because the value it updates is called delegatedTo, so this is consistent (it's just that delegatedTo is weird for a variable name)