docs: add/update/fix comments

Author: MerlinEgalite

src/chainlink/Oracle2.sol

@@ -8,17 +8,18 @@ import {AggregatorV3Interface, DataFeedLib} from "./libraries/DataFeedLib.sol";
 contract Oracle2 is IOracle {
     using DataFeedLib for AggregatorV3Interface;
 
-    /* CONSTANT */
+    /* IMMUTABLES */
 
     /// @notice Base feed.
     AggregatorV3Interface public immutable BASE_FEED;
     /// @notice Quote feed.
     AggregatorV3Interface public immutable QUOTE_FEED;
-    /// @notice Price scale factor, computed at contract creation.
+    /// @notice Price scale factor.
     uint256 public immutable SCALE_FACTOR;
 
     /* CONSTRUCTOR */
 
+    /// @dev Initializes the contract.
     /// @param baseFeed Base feed. Pass address zero if the price = 1.
     /// @param quoteFeed Quote feed. Pass address zero if the price = 1.
     /// @param baseTokenDecimals Base token decimals.
@@ -34,7 +35,7 @@ contract Oracle2 is IOracle {
         // We note pB the base price, and pQ the quote price (price of 1e(decimals) asset).
         // We want to return 1e36 * (pB/1e(bDecimals) / (pQ/1e(qDecimals)).
         // Chainlink returns pB * bFeedPrecision and pQ * qFeedPrecision.
-        // So we have 1e36 * (pB/1e(bDecimals) / (pQ/1e(qDecimals) = pB * 1e(bFeedPrecision) * SCALE_FACTOR / (pQ *
+        // So we have 1e36 * (pB/1e(bDecimals) / (pQ/1e(qDecimals)) = pB * 1e(bFeedPrecision) * SCALE_FACTOR / (pQ *
         // 1e(qFeedPrecision))
         // So SCALE_FACTOR = 1e36 / 1e(bDecimals) * 1e(qDecimals) * 1e(qFeedPrecision) / 1e(bFeedPrecision)
         // So SCALE_FACTOR = 1e(36 + qDecimals + qFeedPrecision - bDecimals - bFeedPrecision)

src/chainlink/Oracle4.sol

@@ -8,7 +8,7 @@ import {AggregatorV3Interface, DataFeedLib} from "./libraries/DataFeedLib.sol";
 contract Oracle4 is IOracle {
     using DataFeedLib for AggregatorV3Interface;
 
-    /* CONSTANT */
+    /* IMMUTABLES */
 
     /// @notice First base feed.
     AggregatorV3Interface public immutable FIRST_BASE_FEED;
@@ -18,11 +18,12 @@ contract Oracle4 is IOracle {
     AggregatorV3Interface public immutable FIRST_QUOTE_FEED;
     /// @notice Second quote feed.
     AggregatorV3Interface public immutable SECOND_QUOTE_FEED;
-    /// @notice Price scale factor, computed at contract creation.
+    /// @notice Price scale factor.
     uint256 public immutable SCALE_FACTOR;
 
     /* CONSTRUCTOR */
 
+    /// @dev Initializes the contract.
     /// @param firstBaseFeed First base feed. Pass address zero if the price = 1.
     /// @param secondBaseFeed Second base feed. Pass address zero if the price = 1.
     /// @param firstQuoteFeed Quote feed. Pass address zero if the price = 1.

src/chainlink/libraries/DataFeedLib.sol

@@ -1,10 +1,12 @@
 // SPDX-License-Identifier: UNLICENSED
 pragma solidity ^0.8.0;
 
-import {ErrorsLib} from "./ErrorsLib.sol";
 import {AggregatorV3Interface} from "chainlink/contracts/src/v0.8/interfaces/AggregatorV3Interface.sol";
 
+import {ErrorsLib} from "./ErrorsLib.sol";
+
 library DataFeedLib {
+    /// @dev Returns the latest price of a `feed`.
     /// @dev Performing some security checks and returns the latest price of a feed.
     /// @dev When `feed` is the address zero, returns 1.
     function getPrice(AggregatorV3Interface feed) internal view returns (uint256) {

src/chainlink/libraries/ErrorsLib.sol

@@ -2,5 +2,6 @@
 pragma solidity ^0.8.0;
 
 library ErrorsLib {
+    /// @notice Thrown when the answer returned by a Chainlink feed is negative.
     string constant NEGATIVE_ANSWER = "negative answer";
 }