add natspec

packages/world/src/modules/core/LimitedCallContext.sol

@@ -1,6 +1,18 @@
 // SPDX-License-Identifier: MIT
 pragma solidity >=0.8.21;
 
+/**
+ * @title LimitedCallContext
+ * @dev Systems are expected to be always called via the central World contract.
+ * Depending on whether it is a root or non-root system, the call is performed via `delegatecall` or `call`.
+ * Since Systems are expected to be stateless and only interact with the World state,
+ * it is normally not necessary to prevent direct calls to the systems.
+ * However, since the `CoreSystem` is known to always be registered as a root system in the World,
+ * it is always expected to be delegatecalled, so we made this expectation explicit by reverting if it is not delegatecalled.
+ *
+ * @dev Based on OpenZeppelin's UUPSUpgradeable.sol
+ * https://github.com/OpenZeppelin/openzeppelin-contracts/blob/v5.0.0/contracts/proxy/utils/UUPSUpgradeable.sol#L50
+ */
 contract LimitedCallContext {
   address private immutable __self = address(this);