lint: resolve shift/reduce conflict in notype_direct_decl

When a notype_direct_decl was followed by a type_attribute_list, and the
next token was another type_attribute, the parser could either continue
the current type_attribute_list or start a new one.  Either way has the
same effect since type_attribute_list has no associated action.

This reduces the conflicts by 4, one for each of T_ALIGNAS, T_ATTRIBUTE,
T_NORETURN, T_PACKED.  There are several other conflicts involving these
4 tokens, but they are harder to fix.

No functional change.

(rillig)