[clang-tidy] readability-redundant-casting should support shared pointer casting

```
std::shared_ptr value = std::make_shared(42);
std::shared_ptr result = std::static_pointer_cast(value); // redindant static_pointer_cast
```

```
boost::shared_ptr value = boost::make_shared(42);
boost::shared_ptr result = boost::static_pointer_cast(value); // redindant static_pointer_cast
```

Start at the clang-tidy readability-redundant-casting check named in the issue and reproduce the std::shared_ptr and boost::shared_ptr examples. Done means redundant static_pointer_cast calls in both examples are recognized by the check, with coverage for the demonstrated cases.

Written by the indexing model from the issue text.