Fixed a typo in detector where *callcode* was specified as *codecall*. Added a test to verify the fix.

slither/detectors/statements/controlled_delegatecall.py

@@ -24,7 +24,7 @@ contract Delegatecall{
     }
 }
 ```
-Bob calls `delegate` and delegate the execution to its malicious contract. As a result, Bob withdraws the funds of the contract and destruct it.'''
+Bob calls `delegate` and delegates the execution to its malicious contract. As a result, Bob withdraws the funds of the contract and destructs it.'''
 
     WIKI_RECOMMENDATION = 'Avoid using `delegatecall`. Use only trusted destinations.'
 
@@ -32,7 +32,7 @@ Bob calls `delegate` and delegate the execution to its malicious contract. As a
         ret = []
         for node in function.nodes:
             for ir in node.irs:
-                if isinstance(ir, LowLevelCall) and ir.function_name in ['delegatecall', 'codecall']:
+                if isinstance(ir, LowLevelCall) and ir.function_name in ['delegatecall', 'callcode']:
                     if is_tainted(ir.destination, function.contract):
                         ret.append(node)
         return ret

tests/controlled_delegatecall.sol

@@ -5,6 +5,10 @@ contract C{
 
     bytes4 func_id;
 
+    function bad_callcode_call(bytes memory data) public{
+        addr_bad.callcode(data);
+    }
+
     function bad_delegate_call(bytes memory data) public{
         addr_good.delegatecall(data);
         addr_bad.delegatecall(data);