Grammar correction in utilities doc (#2952)

Fix grammar in a sentence

(cherry picked from commit b5daea6d5f)

docs/modules/ROOT/pages/utilities.adoc

@@ -31,7 +31,7 @@ xref:api:cryptography.adoc#MerkleProof[`MerkleProof`] provides xref:api:cryptogr
 [[introspection]]
 == Introspection
 
-In Solidity, it's frequently helpful to know whether or not a contract supports an interface you'd like to use. ERC165 is a standard that helps do runtime interface detection. Contracts provides helpers both for implementing ERC165 in your contracts and querying other contracts:
+In Solidity, it's frequently helpful to know whether or not a contract supports an interface you'd like to use. ERC165 is a standard that helps do runtime interface detection. Contracts provide helpers both for implementing ERC165 in your contracts and querying other contracts:
 
 * xref:api:introspection.adoc#IERC165[`IERC165`] — this is the ERC165 interface that defines xref:api:introspection.adoc#IERC165-supportsInterface-bytes4-[`supportsInterface`]. When implementing ERC165, you'll conform to this interface.
 * xref:api:introspection.adoc#ERC165[`ERC165`] — inherit this contract if you'd like to support interface detection using a lookup table in contract storage. You can register interfaces using xref:api:introspection.adoc#ERC165-_registerInterface-bytes4-[`_registerInterface(bytes4)`]: check out example usage as part of the ERC721 implementation.