Remove UNUSED

The `UNUSED` macro is used to mark a variable as unused but with a name.
Those usages are replaced with comments so that `UNUSED` can be removed.

https://isocpp.github.io/CppCoreGuidelines/CppCoreGuidelines#Rf-unused

source/scriptinterface/ScriptStats.cpp

@@ -105,7 +105,7 @@ CStr CScriptStatsTable::GetCellText(size_t row, size_t col)
 	}
 }
 
-AbstractProfileTable* CScriptStatsTable::GetChild(size_t UNUSED(row))
+AbstractProfileTable* CScriptStatsTable::GetChild(size_t /*row*/)
 {
 	return 0;
 }