rdg: use repo name

[tshepang]

The complete name is Rust Compiler Development Guide, which is a mouthful. So, use the repo name, because Rustc Dev Guide would be a third form.

Rendered

[rustbot]

Failed to set assignee to jyn514: invalid assignee

Note: Only org members with at least the repository "read" role, users with write permissions, or people who have commented on the PR may be assigned.

[rustbot]

r? @jyn514

rustbot has assigned @jyn514.
They will have a look at your PR within the next two weeks and either review your PR or reassign to another reviewer.

Use r? to explicitly pick a reviewer

[jieyouxu]

No strong opinions, seems fine.

[apiraino]

why this?

I feel the documentation should instead explicitate and clarify our internal jargon/abbreviations (might have benefits also on a SEO level)

[tshepang]

@apiraino we could expand on what the formal name is in the intro paragraph