Warn for (list)string_var or (list)key_var in LSO.

[Sei-Lisa]

LSO has a weird bug. Variables of type string may have values of type key, and vice versa. This happens with implicit or explicit type casts. For example:

key x = llGenerateKey();
string mystring = x; // implicit type cast
string myotherstring = (string)x; // explicit type cast

After the above code, both mystring and myotherstring hold values of type key, despite the variable being of type string. This is actually only visible when they are type cast to list:

list mylist = (list)mystring;
if (llGetListEntryType(mylist, 0) == TYPE_STRING) llOwnerSay("the list entry is a string");
else if (llGetListEntryType(mylist, 0) == TYPE_KEY) llOwnerSay("the list entry is a key");
else llOwnerSay("not string nor key?!");

The above code prints "the list entry is a key" in LSO (in Mono it correctly prints "the list entry is a string").

A workaround is to use square brackets instead of a typecast:

list mylist = [mystring];
if (llGetListEntryType(mylist, 0) == TYPE_STRING) llOwnerSay("the list entry is a string");
else if (llGetListEntryType(mylist, 0) == TYPE_KEY) llOwnerSay("the list entry is a key");
else llOwnerSay("not string nor key?!");

The above code correctly prints "the list entry is a string" in both LSO and Mono.

It would be nice if lslint warned about typecasts of string or key variables to list when in LSO mode.