docs: update release procedure[skip ci] (#2415)

RELEASE_PROCEDURE.md

@@ -5,7 +5,7 @@ library.
 
 Nix uses [cargo release](https://github.com/crate-ci/cargo-release) to automate
 the release process. Based on changes since the last release, pick a new
-version number following semver conventions. For nix, a change that drops
+version number following semver conventions. For Nix, a change that drops
 support for some Rust versions counts as a breaking change, and requires a
 major bump.
 
@@ -14,24 +14,53 @@ The release is prepared as follows:
 > NOTE: the following procedure should be done directly against the master 
 > branch of the repo.
 
-- Ask for a new libc version if, necessary. It usually is. Then update the
-  dependency in `Cargo.toml` to rely on a release from crates.io.
+- Clone the `nix-rust/nix` repository with your preferred way, and `cd` to it:
+
+  ```sh
+  $ git clone https://github.com/nix-rust/nix.git
+  $ cd nix
+  ```
+
+- If we are using `libc` from git, replace it with a usable release from crates.io.
 
   ```diff
   [dependencies]
   -libc = { git = "https://github.com/rust-lang/libc", rev = "<Revision>", features = ["extra_traits"] }
-  +libc = { version = "<New Version>", features = ["extra_traits"] }
+  +libc = { version = "<Version>", features = ["extra_traits"] }
   ```
 
 - Update the version number in `Cargo.toml`
 - Generate `CHANGELOG.md` for this release by 
-  `towncrier build --version=<VERSION> --yes`
+
+  ```sh
+  $ towncrier build --version=<VERSION> --yes
+  Loading template...
+  Finding news fragments...
+  Rendering news fragments...
+  Writing to newsfile...
+  Staging newsfile...
+  Removing the following files:
+  nix/changelog/xxxx.xxxx.md
+  nix/changelog/xxxx.xxxx.md
+  ...
+  nix/changelog/xxxx.xxxx.md
+  Removing news fragments...
+  Done!
+  ``` 
+
+- Push the changes made by the above steps to the master branch
 
 - Ensure you have a crates.io token 
-  1. With the `publich-update` scope
+  1. With the `publish-update` scope
   2. Can be used for crate `nix`
   3. It is set via `cargo login`
 
+  If not, create a new token [here](https://crates.io/settings/tokens), and set
+  it. 
+
 - Confirm that everything's ready for a release by running
-  `cargo release <patch|minor|major>`
-- Create the release with `cargo release -x <patch|minor|major>`
+  `cargo release <VERSION>`
+- Create the release with `cargo release -x <VERSION>`, this step will publish
+  the version to crates.io and push the new version tag to GitHub.
+
+- Congratulations on a new Nix release!