docs: add description of the contracts

Author: MerlinEgalite

src/chainlink/Oracle2.sol

@@ -5,6 +5,11 @@ import {IOracle} from "morpho-blue/interfaces/IOracle.sol";
 
 import {AggregatorV3Interface, DataFeedLib} from "./libraries/DataFeedLib.sol";
 
+/// @title Oracle2
+/// @author Morpho Labs
+/// @custom:contact [email protected]
+/// @notice Oracle using 2 Chainlink-compliant feeds to compute the price of a collateral token quoted in a borrowable
+/// token within a Morpho Blue market.
 contract Oracle2 is IOracle {
     using DataFeedLib for AggregatorV3Interface;
 

src/chainlink/Oracle4.sol

@@ -5,6 +5,11 @@ import {IOracle} from "morpho-blue/interfaces/IOracle.sol";
 
 import {AggregatorV3Interface, DataFeedLib} from "./libraries/DataFeedLib.sol";
 
+/// @title Oracle4
+/// @author Morpho Labs
+/// @custom:contact [email protected]
+/// @notice Oracle using 4 Chainlink-compliant feeds to compute the price of a collateral token quoted in a borrowable
+/// token within a Morpho Blue market.
 contract Oracle4 is IOracle {
     using DataFeedLib for AggregatorV3Interface;
 

src/chainlink/libraries/DataFeedLib.sol

@@ -5,6 +5,10 @@ import {AggregatorV3Interface} from "chainlink/contracts/src/v0.8/interfaces/Agg
 
 import {ErrorsLib} from "./ErrorsLib.sol";
 
+/// @title DataFeedLib
+/// @author Morpho Labs
+/// @custom:contact [email protected]
+/// @notice Library exposing functions to interact with a Chainlink-compliant feed.
 library DataFeedLib {
     /// @dev Returns the latest price of a `feed`.
     /// @dev Performing some security checks and returns the latest price of a feed.

src/chainlink/libraries/ErrorsLib.sol

@@ -1,6 +1,10 @@
 // SPDX-License-Identifier: UNLICENSED
 pragma solidity ^0.8.0;
 
+/// @title ErrorsLib
+/// @author Morpho Labs
+/// @custom:contact [email protected]
+/// @notice Library exposing error messages.
 library ErrorsLib {
     /// @notice Thrown when the answer returned by a Chainlink feed is negative.
     string constant NEGATIVE_ANSWER = "negative answer";

test/chainlink/Oracle4Test.sol

@@ -26,7 +26,8 @@ contract OracleTest is Test {
         (, int256 quoteAnswer,,,) = usdcUsdFeed.latestRoundData();
         assertEq(
             oracle.price(),
-            (uint256(firstBaseAnswer) * uint256(secondBaseAnswer) * 10 ** (36 + 8 + 6 - 8 - 8 - 8)) / uint256(quoteAnswer)
+            (uint256(firstBaseAnswer) * uint256(secondBaseAnswer) * 10 ** (36 + 8 + 6 - 8 - 8 - 8))
+                / uint256(quoteAnswer)
         );
     }
 
@@ -37,7 +38,8 @@ contract OracleTest is Test {
         (, int256 secondQuoteAnswer,,,) = btcUsdFeed.latestRoundData();
         assertEq(
             oracle.price(),
-            (uint256(baseAnswer) * 10 ** (36 + 8 + 8 + 8 - 6 - 8)) / (uint256(firstQuoteAnswer) * uint256(secondQuoteAnswer))
+            (uint256(baseAnswer) * 10 ** (36 + 8 + 8 + 8 - 6 - 8))
+                / (uint256(firstQuoteAnswer) * uint256(secondQuoteAnswer))
         );
     }