docs: minor - spelling, grammar (#2273)

contracts/token/ERC1155/README.adoc

@@ -4,7 +4,7 @@ This set of interfaces and contracts are all related to the https://eips.ethereu
 
 The EIP consists of three interfaces which fulfill different roles, found here as `IERC1155`, `IERC1155MetadataURI` and `IERC1155Receiver`.
 
-`ERC1155` implement the mandatory `IERC1155` interface, as well as the optional extension `IERC1155MetadataURI` by relying on the substition mechanism to use the same URI for all token types, dramatically reducing gas costs.
+`ERC1155` implements the mandatory `IERC1155` interface, as well as the optional extension `IERC1155MetadataURI`, by relying on the substitution mechanism to use the same URI for all token types, dramatically reducing gas costs.
 
 `ERC1155Holder` implements the `IERC1155Receiver` interface for contracts that can receive (and hold) ERC1155 tokens.