Update changesets and fix some comments

.changeset/odd-files-protect.md

@@ -2,4 +2,4 @@
 'openzeppelin-solidity': minor
 ---
 
-`Hashes`: new library of commonly used hashes.
+`Hashes`: A library with commonly used hash functions.

.changeset/warm-sheep-cover.md

@@ -2,4 +2,4 @@
 'openzeppelin-solidity': minor
 ---
 
-`MerkleTree`: a new data structure that keep track of merkle roots as values are inserted into a merkle tree.
+`MerkleTree`: A data structure that allows inserting elements into a merkle tree and updating its root hash.

contracts/utils/structs/MerkleTree.sol

@@ -12,15 +12,15 @@ import {Panic} from "../Panic.sol";
  * are not stored, but can be proven to be part of the tree.
  *
  * The history of merkle roots allow inclusion proofs to remain valid even if leaves are inserted into the tree between
- *  the moment the proof is generated and the moment it's verified.
+ * the moment the proof is generated and the moment it's verified.
  *
  * Each tree can be customized to use specific
  * - depth
  * - length of the root history
  * - zero values (for "empty" leaves)
  * - hash function
  *
- * WARNING: By design, the tree include zero leaves. Customizing the "zero value" might be necessary to ensure that
+ * IMPORTANT: By design, the tree include zero leaves. Customizing the "zero value" might be necessary to ensure that
  * empty leaves being provably part of the tree is not a security issue.
  *
  * _Available since v5.1._
@@ -39,7 +39,7 @@ library MerkleTree {
 
     /**
      * @dev The `sides` and `zero` arrays are set, at initialization, to have a length equal to the depth of the tree.
-     * No push/pop operations should be performed of these array, and their lengths should not be updated.
+     * No push/pop operations should be performed of these arrays, and their lengths should not be updated.
      *
      * The hashing function used during initialization to compute the `zeros` values (value of a node at a given depth
      * for which the subtree is full of zero leaves). This function is kept in the structure for handling insertions.
@@ -58,7 +58,7 @@ library MerkleTree {
     }
 
     /**
-     * @dev Initialize using the default hash
+     * @dev Initialize using {Hashes-stdPairHash} as the hashing function for a pair of leaves.
      */
     function setup(Bytes32MerkleTree storage self, uint256 depth, bytes32 zero) internal {
         return setup(self, depth, zero, Hashes.stdPairHash);