This follows the Rust naming.

Co-Authored-By: Frederik Rietdijk <[email protected]>

Co-Authored-By: Frederik Rietdijk <[email protected]>

Transposition typo GitHub <-> Git

This is an implementation detail, not really relevant here.

NixOS/nix#3045

This removes:

* Discussion of UI (`nix`) changes. The `nix` CLI is experimental
  anyway so no need to discuss it in an RFC.

* Flake references. These are mainly of use in the CLI. In flake.nix,
  we can use attrsets instead (e.g. `{ type = "github"; owner =
  "NixOS"; repo = "nixpkgs"; }` instead of `github:NixOS/nixpkgs`).

* The well-known outputs. The flake mechanism doesn't care about what
  the outputs are, only tools (like `nix`) care about particular
  outputs.

* Most of the discussion about registries. There are still indirect
  flake inputs (e.g. `nixpkgs`) but how these are resolved is an
  implementation detail of tools that update the lock file.

This allows circular dependencies between flakes and makes lock files
more compact (e.g. you can deduplicate all the 'nixpkgs' inputs).

Future editions of flakes or the Nix language can be supported by
renaming flake.nix (e.g. flake-v2.nix). This avoids a bootstrap
problem where we don't know which grammar to use to parse
flake*.nix. It also allows a project to support multiple flake
editions, in theory.

Co-authored-by: Jan Tojnar <[email protected]>

NixOS/nix@950b468