docs: mark INativeToken functions as external (#66)

Author: johnletey

crates/ev-precompiles/README.md

@@ -22,10 +22,10 @@ The precompile is deployed at a reserved address in the precompile address space
 
 ```solidity
 interface INativeToken {
-    function mint(address to, uint256 amount);
-    function burn(address from, uint256 amount);
-    function addToAllowList(address account);
-    function removeFromAllowList(address account);
+    function mint(address to, uint256 amount) external;
+    function burn(address from, uint256 amount) external;
+    function addToAllowList(address account) external;
+    function removeFromAllowList(address account) external;
 }
 ```
 

crates/ev-precompiles/src/mint.rs

@@ -12,10 +12,10 @@ use std::sync::OnceLock;
 
 sol! {
     interface INativeToken {
-        function mint(address to, uint256 amount);
-        function burn(address from, uint256 amount);
-        function addToAllowList(address account);
-        function removeFromAllowList(address account);
+        function mint(address to, uint256 amount) external;
+        function burn(address from, uint256 amount) external;
+        function addToAllowList(address account) external;
+        function removeFromAllowList(address account) external;
     }
 }
 

docs/adr/ADR-0002-native-minting-precompile.md

@@ -45,10 +45,10 @@ We will implement a custom precompile for native token minting. The precompile w
 
 ```solidity
 interface INativeToken {
-    function mint(address to, uint256 amount);
-    function burn(address from, uint256 amount);
-    function addToAllowList(address account);
-    function removeFromAllowList(address account);
+    function mint(address to, uint256 amount) external;
+    function burn(address from, uint256 amount) external;
+    function addToAllowList(address account) external;
+    function removeFromAllowList(address account) external;
 }
 ```