Merge pull request aave#121 from aave/docs/rewards-struct-docs

docs: Add docs to Rewards structs

contracts/rewards/RewardsDistributor.sol

@@ -14,19 +14,19 @@ import {RewardsDataTypes} from './libraries/RewardsDataTypes.sol';
  **/
 abstract contract RewardsDistributor is IRewardsDistributor {
   using SafeCast for uint256;
-  // manager of incentives
+  // Manager of incentives
   address internal _emissionManager;
 
-  // asset => AssetData
+  // Map of rewarded asset addresses and their data (assetAddress => assetData)
   mapping(address => RewardsDataTypes.AssetData) internal _assets;
 
-  // reward => enabled
+  // Map of reward assets (rewardAddress => enabled)
   mapping(address => bool) internal _isRewardEnabled;
 
-  // global rewards list
+  // Rewards list
   address[] internal _rewardsList;
 
-  //global assets list
+  // Assets list
   address[] internal _assetsList;
 
   modifier onlyEmissionManager() {
@@ -482,6 +482,7 @@ abstract contract RewardsDistributor is IRewardsDistributor {
 
   /**
    * @dev Calculates the next value of an specific distribution index, with validations
+   * @param rewardData Storage pointer to the distribution reward config
    * @param totalSupply of the asset being rewarded
    * @param assetUnit One unit of asset (10**decimals)
    * @return The new index.

contracts/rewards/libraries/RewardsDataTypes.sol

@@ -22,22 +22,33 @@ library RewardsDataTypes {
   }
 
   struct UserData {
-    uint104 index; // matches reward index
+    // Liquidity index of the reward distribution for the user
+    uint104 index;
+    // Amount of accrued rewards for the user since last user index update
     uint128 accrued;
   }
 
   struct RewardData {
+    // Liquidity index of the reward distribution
     uint104 index;
+    // Amount of reward tokens distributed per second
     uint88 emissionPerSecond;
+    // Timestamp of the last reward index update
     uint32 lastUpdateTimestamp;
+    // The end of the distribution of rewards (in seconds)
     uint32 distributionEnd;
+    // Map of user addresses and their rewards data (userAddress => userData)
     mapping(address => UserData) usersData;
   }
 
   struct AssetData {
+    // Map of reward token addresses and their data (rewardTokenAddress => rewardData)
     mapping(address => RewardData) rewards;
+    // List of reward token addresses for the asset
     mapping(uint128 => address) availableRewards;
+    // Count of reward tokens for the asset
     uint128 availableRewardsCount;
+    // Number of decimals of the asset
     uint8 decimals;
   }
 }