[pseudo] Apply the function-declarator to member functions.

[hokein]

Summary

A followup patch of d489b3807f096584175c321ce7f20e9dcd49b1da, but for
member functions, this will eliminate a false parse of member
declaration.

clang-tools-extra/pseudo/lib/cxx/cxx.bnf

 member-declaration := template-declaration
 member-declaration := explicit-specialization
 member-declaration := deduction-guide
 member-declaration := alias-declaration
 member-declaration := opaque-enum-declaration
 member-declaration := empty-declaration
 member-declarator-list := member-declarator
 member-declarator-list := member-declarator-list , member-declarator
-member-declarator := declarator virt-specifier-seq_opt pure-specifier_opt
-member-declarator := declarator requires-clause
-member-declarator := declarator brace-or-equal-initializer
+member-declarator := function-declarator virt-specifier-seq_opt pure-specifier_opt
+member-declarator := function-declarator requires-clause
+member-declarator := non-function-declarator brace-or-equal-initializer_opt
 member-declarator := IDENTIFIER_opt : constant-expression brace-or-equal-initializer_opt
 virt-specifier-seq := virt-specifier
 virt-specifier-seq := virt-specifier-seq virt-specifier
 virt-specifier := contextual-override
 virt-specifier := contextual-final
 pure-specifier := = contextual-zero
 conversion-function-id := OPERATOR conversion-type-id
 conversion-type-id := type-specifier-seq conversion-declarator_opt

clang-tools-extra/pseudo/test/cxx/declator-member-function.cpp

+// RUN: clang-pseudo -grammar=cxx -source=%s --print-forest | FileCheck %s
+
+// Similiar to declarator-function.cpp, but for member functions.
+class Foo {
+  void foo() {};
+// CHECK-NOT: member-declarator := declarator brace-or-equal-initializer
+// CHECK: member-declaration~function-definition := decl-specifier-seq function-declarator function-body
+// CHECK-NOT: member-declarator := declarator brace-or-equal-initializer
+};