bug: defaulted `friend` operators get incorrectly parsed as declarations

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Tree-Sitter CLI Version, if relevant (output of tree-sitter --version)

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Describe the bug

In C++20, operator== and operator<=> can get marked as default. These operators do not have to be methods and can be friends instead. This does not get parsed correctly.

Steps To Reproduce/Bad Parse Tree

Example (adapted from Default comparisons (cppreference))

struct X
{
    bool operator==(const X&) const = default;
    friend bool operator==(X, X) = default;
};

(Bad) tree:

(translation_unit ; [0, 0] - [5, 0] cpp
  (struct_specifier ; [0, 0] - [4, 1] cpp
    name: (type_identifier) ; [0, 7] - [0, 8] cpp
    body: (field_declaration_list ; [1, 0] - [4, 1] cpp
      (function_definition ; [2, 4] - [2, 46] cpp
        type: (primitive_type) ; [2, 4] - [2, 8] cpp
        declarator: (function_declarator ; [2, 9] - [2, 35] cpp
          declarator: (operator_name) ; [2, 9] - [2, 19] cpp
          parameters: (parameter_list ; [2, 19] - [2, 29] cpp
            (parameter_declaration ; [2, 20] - [2, 28] cpp
              (type_qualifier) ; [2, 20] - [2, 25] cpp
              type: (type_identifier) ; [2, 26] - [2, 27] cpp
              declarator: (abstract_reference_declarator))) ; [2, 27] - [2, 28] cpp
          (type_qualifier)) ; [2, 30] - [2, 35] cpp
        (default_method_clause)) ; [2, 36] - [2, 46] cpp
      (friend_declaration ; [3, 4] - [3, 43] cpp
        (declaration ; [3, 11] - [3, 43] cpp
          type: (primitive_type) ; [3, 11] - [3, 15] cpp
          declarator: (init_declarator ; [3, 16] - [3, 42] cpp
            declarator: (function_declarator ; [3, 16] - [3, 32] cpp
              declarator: (operator_name) ; [3, 16] - [3, 26] cpp
              parameters: (parameter_list ; [3, 26] - [3, 32] cpp
                (parameter_declaration ; [3, 27] - [3, 28] cpp
                  type: (type_identifier)) ; [3, 27] - [3, 28] cpp
                (parameter_declaration ; [3, 30] - [3, 31] cpp
                  type: (type_identifier)))) ; [3, 30] - [3, 31] cpp
            value: (identifier))))))) ; [3, 35] - [3, 42] cpp

See that the friend function with = default got parsed as a declaration, and the default got parsed as a value, not a keyword.

Expected Behavior/Parse Tree

Defaulted friend functions (currently probably only operator== and operator<=>) should get parsed as such.

Repro

(see example above bad tree)

Start with the C++ example and bad parse tree in this issue, then inspect the grammar rules handling friend declarations, operator names, and default method clauses. Confirm the existing parse and identify the grammar entry point responsible; done means the friend operator with = default is represented as a defaulted function rather than a declaration whose value is default.