[add definition] for defaulted functions

i came across a small issue with the refactoring tools: if i'm having this code:

struct foo
{
    virtual ~foo() = default;
};

the refactoring tools provide an option "add definition". "add definition outside class" will generate code like this:

struct foo
{
    virtual ~foo() = default;
};

inline foo::~foo()
{}

seems that the `= default` isn't handled by the code model so the defaulted dtor is treated as declaration, not as definition.

expected behaviour: "move definition" in the context menu and resulting in something like:

struct foo
{
    virtual ~foo();
};

inline foo::~foo() = default;