fix(RingBufferLib): add Natspec doc.

contracts/libraries/RingBufferLib.sol

@@ -3,15 +3,27 @@
 pragma solidity 0.8.6;
 
 library RingBufferLib {
-    /// @notice Returns TWAB index.
-    /// @dev `twabs` is a circular buffer of `MAX_CARDINALITY` size equal to 32. So the array goes from 0 to 31.
-    /// @dev In order to navigate the circular buffer, we need to use the modulo operator.
-    /// @dev For example, if `_index` is equal to 32, `_index % MAX_CARDINALITY` will return 0 and will point to the first element of the array.
-    /// @param _index Index used to navigate through `twabs` circular buffer.
+    /**
+    * @notice Returns wrapped TWAB index.
+    * @dev  In order to navigate the TWAB circular buffer, we need to use the modulo operator.
+    * @dev  For example, if `_index` is equal to 32 and the TWAB circular buffer is of `_cardinality` 32,
+    *       it will return 0 and will point to the first element of the array.
+    * @param _index Index used to navigate through the TWAB circular buffer.
+    * @param _cardinality TWAB buffer cardinality.
+    * @return TWAB index.
+    */
     function wrap(uint256 _index, uint256 _cardinality) internal pure returns (uint256) {
         return _index % _cardinality;
     }
 
+    /**
+    * @notice Returns the `_index` offsetted by `_amount`.
+    * @dev  We add `_cardinality` to `_index` to be able to offset event if `_amount` is superior to `_cardinality`.
+    * @param _index Index to offset.
+    * @param _amount Amount we want to offset the `_index` by.
+    * @param _cardinality TWAB buffer cardinality.
+    * @return Offsetted index.
+     */
     function offset(
         uint256 _index,
         uint256 _amount,
@@ -20,10 +32,12 @@ library RingBufferLib {
         return wrap(_index + _cardinality - _amount, _cardinality);
     }
 
-    /// @notice Returns the index of the last recorded TWAB
-    /// @param _nextAvailableIndex The next available twab index.  This will be recorded to next.
-    /// @param _cardinality The cardinality of the TWAB history.
-    /// @return The index of the last recorded TWAB
+    /**
+    * @notice Returns index of the last recorded TWAB.
+    * @param _nextAvailableIndex Next available twab index to which will be recorded the next TWAB.
+    * @param _cardinality TWAB buffer cardinality.
+    * @return Index of the last recorded TWAB.
+     */
     function mostRecentIndex(uint256 _nextAvailableIndex, uint256 _cardinality)
         internal
         pure
@@ -36,6 +50,12 @@ library RingBufferLib {
         return wrap(_nextAvailableIndex + _cardinality - 1, _cardinality);
     }
 
+    /**
+    * @notice Returns the next available TWAB index.
+    * @param _currentIndex Current TWAB buffer index.
+    * @param _cardinality TWAB buffer cardinality.
+    * @return Next available TWAB index.
+    */
     function nextIndex(uint256 _currentIndex, uint256 _cardinality)
         internal
         pure