Add missing docstrings

ethereum/contracts/upgrades/BaseZkSyncUpgrade.sol

@@ -59,6 +59,9 @@ abstract contract BaseZkSyncUpgrade is Base {
     event UpgradeComplete(uint256 indexed newProtocolVersion, bytes32 indexed l2UpgradeTxHash, ProposedUpgrade upgrade);
 
     /// @notice The main function that will be provided by the upgrade proxy
+    /// @dev This is a virtual function and should be overridden by custom upgrade implementations.
+    /// @param _proposedUpgrade The upgrade to be executed.
+    /// @return The hash of the L2 system contract upgrade transaction.
     function upgrade(ProposedUpgrade calldata _proposedUpgrade) public virtual returns (bytes32) {
         // Note that due to commitment delay, the timestamp of the L2 upgrade batch may be earlier than the timestamp
         // of the L1 block at which the upgrade occured. This means that using timestamp as a signifier of "upgraded"

zksync/contracts/bridge/L2ERC20Bridge.sol

@@ -37,6 +37,10 @@ contract L2ERC20Bridge is IL2Bridge, Initializable {
         _disableInitializers();
     }
 
+    /// @notice Initializes the bridge contract for later use. Expected to be used in the proxy.
+    /// @param _l1Bridge The address of the L1 Bridge contract.
+    /// @param _l2TokenProxyBytecodeHash The bytecode hash of the proxy for tokens deployed by the bridge.
+    /// @param _governor The address of the governor contract.
     function initialize(address _l1Bridge, bytes32 _l2TokenProxyBytecodeHash, address _governor) external initializer {
         require(_l1Bridge != address(0), "bf");
         require(_l2TokenProxyBytecodeHash != bytes32(0), "df");

zksync/contracts/bridge/L2StandardERC20.sol

@@ -100,7 +100,14 @@ contract L2StandardERC20 is ERC20PermitUpgradeable, IL2StandardToken, ERC1967Upg
         emit BridgeInitialize(_l1Address, decodedName, decodedSymbol, decimals_);
     }
 
-    // Method which is to be used by bridge if a token needs to change its name, symbol or decimals.
+    /// @notice Method which is to be used by the governor if a token needs to change its name, symbol or decimals.
+    /// @param _availableGetters The set of getters that the token has.
+    /// @param _newName The new name of the token.
+    /// @param _newSymbol The new symbol of the token.
+    /// @param _newDecimals The new decimals of the token.
+    /// @param _version The version of the token that is to be initialized. The version is the number of times
+    /// the token was reinitialized. The first version is 1.
+    /// @dev The versions must be strictly incrementally increasing, i.e. it is not possible to "jump" between two versions. 
     function reinitializeToken(
         ERC20Getters calldata _availableGetters,
         string memory _newName,