Update ERC-777: fix typo (#182)

* Update ERC-777 : fix typo

same as title

* Add hyphen for `ERC-N`

ERCS/erc-777.md

@@ -130,7 +130,7 @@ The token contract MUST register the `ERC777Token` interface with its own addres
 > and the `keccak256` hash of `ERC777Token` (`0xac7fbab5f54a3ca8194167523c6753bfeb96a445279294b6125b68cce2177054`)
 > as the interface hash.
 
-If the contract has a switch to enable or disable ERC777 functions, every time the switch is triggered,
+If the contract has a switch to enable or disable ERC-777 functions, every time the switch is triggered,
 the token MUST register or unregister the `ERC777Token` interface for its own address accordingly via ERC1820.
 Unregistering implies calling the `setInterfaceImplementer` with the token contract address as the address,
 the `keccak256` hash of `ERC777Token` as the interface hash and `0x0` as the implementer.
@@ -250,7 +250,7 @@ defined under the [operators] for consistency.
 
 *[ERC-20] compatibility requirement*:  
 The decimals of the token MUST always be `18`.
-For a *pure* ERC777 token the [ERC-20] `decimals` function is OPTIONAL,
+For a *pure* ERC-777 token the [ERC-20] `decimals` function is OPTIONAL,
 and its existence SHALL NOT be relied upon when interacting with the token contract.
 (The decimal value of `18` is implied.)
 For an [ERC-20] compatible token, the `decimals` function is REQUIRED and MUST return `18`.
@@ -719,7 +719,7 @@ MAY use the information to decide if they wish to reject the transaction.
 
 ``` solidity
 event Burned(
-    ddress indexed operator,
+    address indexed operator,
     address indexed from,
     uint256 amount,
     bytes data,
@@ -912,7 +912,7 @@ then the token contract:
 - MUST `revert` if the `tokensReceived` hook is called from a mint or send call.
 
 - SHOULD continue processing the transaction
-  if the `tokensReceived` hook is called from an ERC20 `transfer` or `transferFrom` call.
+  if the `tokensReceived` hook is called from an ERC-20 `transfer` or `transferFrom` call.
 
 *NOTE*: A regular address MAY register a different address—the address of a contract—implementing
 the interface on its behalf.
@@ -1098,7 +1098,7 @@ The first proposal for this registry was [ERC-820].
 Unfortunately, issues emanating from upgrades in the Solidity language to versions 0.5 and above
 resulted in a bug in a separated part of the registry, which required changes.
 This was discovered right after the last call period.
-Attempts made to avoid creating a separate EIP, such as [ERC820a], were rejected.
+Attempts made to avoid creating a separate EIP, such as [ERC-820a], were rejected.
 Hence the standard for the registry used for [ERC-777] became [ERC-1820].
 [ERC-1820] and [ERC-820] are functionally equivalent. [ERC-1820] simply contains the fix for newer versions of Solidity.
 
@@ -1151,12 +1151,12 @@ Note that [ERC-20] functions SHOULD be limited to only being called from old con
 
 If the token implements [ERC-20],
 it MUST register the `ERC20Token` interface with its own address via [ERC-1820].
-This is done by calling the `setInterfaceImplementer` function on the ERC1820 registry
+This is done by calling the `setInterfaceImplementer` function on the ERC-1820 registry
 with the token contract address as both the address and the implementer
 and the `keccak256` hash of `ERC20Token` (`0xaea199e31a596269b42cdafd93407f14436db6e4cad65417994c2eb37381e05a`)
 as the interface hash.
 
-If the contract has a switch to enable or disable ERC20 functions, every time the switch is triggered,
+If the contract has a switch to enable or disable ERC-20 functions, every time the switch is triggered,
 the token MUST register or unregister the `ERC20Token` interface for its own address accordingly via ERC1820.
 Unregistering implies calling the `setInterfaceImplementer` with the token contract address as the address,
 the `keccak256` hash of `ERC20Token` as the interface hash and `0x0` as the implementer.
@@ -1250,7 +1250,7 @@ Copyright and related rights waived via [CC0](../LICENSE.md).
 [ERC-672]: https://github.com/ethereum/EIPs/issues/672
 [ERC-777]: ./eip-777.md
 [ERC-820]: ./eip-820.md
-[ERC820a]: https://github.com/ethereum/EIPs/pull/1758
+[ERC-820a]: https://github.com/ethereum/EIPs/pull/1758
 [ERC-1820]: ./eip-1820.md
 [erc1820-set]: ./eip-1820.md#set-an-interface-for-an-address
 [0xjac]: https://github.com/0xjac