CHECK 2 done

Add support for handling generic types in LLVM backend

- Updated `lb_type_internal` to return a pointer type for unspecialized generics.
- Modified `write_type_to_canonical_string` to handle specialized generics without panicking.
- Enhanced `default_type` to return the default type of specialized generics when applicable.

src/types.cpp

@@ -2932,6 +2932,10 @@ gb_internal Type *default_type(Type *type) {
 		case Basic_UntypedString:     return t_string;
 		case Basic_UntypedRune:       return t_rune;
 		}
+	} else if (type->kind == Type_Generic) {
+		if (type->Generic.specialized) {
+			return default_type(type->Generic.specialized);
+		}
 	}
 	return type;
 }