Add more documentation (#90)

* Add more documentation for earning power

src/GovernanceStaker.sol

@@ -187,6 +187,10 @@ abstract contract GovernanceStaker is INotifiableRewardReceiver, Multicall {
   uint256 public totalEarningPower;
 
   /// @notice Contract that determines a deposit's earning power based on their delegatee.
+  /// @dev An earning power calculator should take into account that a deposit's earning power is an
+  /// uint96. There may be overflow issues within governance staker if this is not taken into
+  /// account. Also, there should be some mechanism to prevent the deposit from frequently being
+  /// bumpable: if earning power changes frequently, this will eat into a users unclaimed rewards.
   IEarningPowerCalculator public earningPowerCalculator;
 
   /// @notice Tracks the total staked by a depositor across all unique deposits.