Switch from RAII to OBRM terminology

[9SMTM6]

Same as in rust-unofficial/patterns#322, as I found out in a discussion, a lot of the documentation - even this official one - still primarily or even exclusively uses RAII terminology for that feature.

AFAIK OBRM is the official term, and based on my own experience and others feedback it's a lot more intuitive.

As referenced in the linked PR I don't want to remove RAII references, just switch to primarily using OBRM terminology, and as with that issue I'll hopefully get to making a PR on this over the weekend, but others can feel free to to it themselves before that. And of course here too I'd first like to know that such a PR would actually be appreciated.

[9SMTM6]

Nomicon:

https://doc.rust-lang.org/nomicon/obrm.html

Relevant section in this book:

https://doc.rust-lang.org/rust-by-example/scope/raii.html

[9SMTM6]

Sadly I was not able to get to both this as well as the pattern book over this weekend, as in the Pattern book there appears to be need for diskussion I priorized that.

If there would be an aknowledgement that this issue and the proposed solution is acceptable that would also be great, I dont want to waste my time.