Better handling of local class when creating local variable-like elements.

[lahodaj]

Consider code like:

void test() {
    record R(int i) {}
    r = new R(0);
}

there's an error on the r = new R(0); line, as r is not defined. There's a fix available for that, but if that's used, the type of the variable will be Record. That's not ideal - R would be much better.

Given that, with the introduction of record, local classes might be more common than before, this PR's goal is to improve handling of local classes in hints that generate variables.

For introduce hint, this PR will detect some variants would not work well, and does not offer them to the user.

What do you think?

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