docs: Added natspec to escrow contract

contracts/escrow.sol

@@ -31,6 +31,14 @@ contract Escrow is Pausable {
     event Paid(uint escrowId);
     event Canceled(uint escrowId);
 
+    /**
+     * @dev Create a new escrow
+     * @param _buyer The address that will perform the buy for the escrow
+     * @param _expirationTime Unix timestamp before the transaction is considered expired
+     * @notice Requires contract to be unpaused.
+     *         The seller needs to be licensed.
+     *         The expiration time must be at least 10min in the future
+     */
     function create(address payable _buyer, uint _expirationTime) public payable whenNotPaused {
         require(_expirationTime > (block.timestamp + 600), "Expiration time must be at least 10min in the future");
         require(msg.value > 0, "ETH amount is required"); // TODO: abstract this to use ERC20. Maybe thru the use of wETH
@@ -48,6 +56,14 @@ contract Escrow is Pausable {
         emit Created(msg.sender, _buyer, msg.value, escrowId);
     }
 
+
+    /**
+     * @dev Release escrow funds to buyer
+     * @param _escrowId Id of the escrow
+     * @notice Requires contract to be unpaused.
+     *         Can only be executed by the seller
+     *         Transaction must not be expired, or previously canceled or released
+     */
     function release(uint _escrowId) public whenNotPaused {
         require(_escrowId < transactions.length, "Invalid escrow id");
 
@@ -64,6 +80,13 @@ contract Escrow is Pausable {
         emit Paid(_escrowId);
     }
 
+    /**
+     * @dev Cancel an escrow operation
+     * @param _escrowId Id of the escrow
+     * @notice Requires contract to be unpaused.
+     *         Can only be executed by the seller
+     *         Transaction must not be expired, or previously canceled or released
+     */
     function cancel(uint _escrowId) public whenNotPaused {
         require(_escrowId < transactions.length, "Invalid escrow id");
 
@@ -79,6 +102,14 @@ contract Escrow is Pausable {
         emit Canceled(_escrowId);
     }
 
+    
+    /**
+     * @dev Withdraws funds to the sellers in case of emergency
+     * @param _escrowId Id of the escrow
+     * @notice Requires contract to be paused.
+     *         Can be executed by anyone
+     *         Transaction must not be canceled or released
+     */
     function withdraw_emergency(uint _escrowId) public whenPaused {
         require(_escrowId < transactions.length, "Invalid escrow id");