Add fn map_values(…) method to Tree<T>

[regexident]

I needed to map trees from one node value type to another and implementing such a mapping via the existing public API was sub-optimal, while with access to the internals it turned out to be trivial.

[adamreichold]

The Clippy lint is unrelated to your change but could fix it nevertheless? Thanks!

[regexident]

The Clippy lint is unrelated to your change but could fix it nevertheless? Thanks!

Done.

[adamreichold]

I'll give it some time for anybody else to have a look and merge if happy. Otherwise I'll merge it tomorrow.

[regexident]

@adamreichold is there a chance to get a release cut with this?

[adamreichold]

@cfvescovo Would you be up to releasing the current state of affairs as 0.9.1?

[cfvescovo]

I may have to do some git tricks to release your fix as 0.9.1 and then the current state (with sort) as 0.10.0. If it's okay for you I will do it this evening (CET time)

[adamreichold]

If you aim for that, then just release 0.10.0 and we'll bump scraper as well. I was suggesting 0.9.1 because we are 0.x and did not make any incompatible changes, i.e. even sort could be in 0.9.1 as it just adds new API surface.

[cfvescovo]

Ok, so I will release 0.10.0. I like keeping patch version bumps for hot fixes