Add Multicall module (#2608)

docs/modules/ROOT/pages/utilities.adoc

@@ -99,3 +99,41 @@ Want to check if an address is a contract? Use xref:api:utils.adoc#Address[`Addr
 
 Want to keep track of some numbers that increment by 1 every time you want another one? Check out xref:api:utils.adoc#Counters[`Counters`]. This is useful for lots of things, like creating incremental identifiers, as shown on the xref:erc721.adoc[ERC721 guide].
 
+=== Multicall
+
+The `Multicall` abstract contract comes with a `multicall` function that bundles together multiple calls in a single external call. With it, external accounts may perform atomic operations comprising several function calls. This is not only useful for EOAs to make multiple calls in a single transaction, it's also a way to revert a previous call if a later one fails.
+
+Consider this dummy contract:
+
+[source,solidity]
+----
+// contracts/Box.sol
+// SPDX-License-Identifier: MIT
+pragma solidity ^0.8.0;
+
+import "@openzeppelin/contracts/utils/Multicall.sol";
+
+contract Box is Multicall {
+    function foo() public {
+        ...
+    }
+
+    function bar() public {
+        ...
+    }
+}
+----
+
+This is how to call the `multicall` function using Truffle, allowing `foo` and `bar` to be called in a single transaction:
+[source,javascript]
+----
+// scripts/foobar.js
+
+const Box = artifacts.require('Box');
+const instance = await Box.new();
+
+await instance.multicall([
+    instance.contract.methods.foo().encodeABI(),
+    instance.contract.methods.bar().encodeABI()
+]);
+----