redirect the entire mutable Nix manual URL to Hydra

also pin some unneeded links to the development version of the Nix
manual to a release

this doesn't address the full issue, because Hydra doesn't do pretty
URLs, and Netlify proxying (the 200 redirect) doesn't seem to actually
work.

_redirects

@@ -33,5 +33,5 @@
 /tutorials/module-system/module-system /tutorials/module-system/deep-dive 301
 
 /permalink/stub-ld /guides/faq#how-to-run-non-nix-executables 301
-/manual/nix/unstable https://hydra.nixos.org/job/nix/master/build.x86_64-linux/latest/download 200
-/manual/nix/development https://hydra.nixos.org/job/nix/master/build.x86_64-linux/latest/download 200
+/manual/nix/unstable/* https://hydra.nixos.org/job/nix/master/build.x86_64-linux/latest/download/1/manual/:splat 200
+/manual/nix/development/* https://hydra.nixos.org/job/nix/master/build.x86_64-linux/latest/download/1/manual/:splat 200

source/concepts/faq.md

@@ -52,7 +52,7 @@ Rolling releases follow [`master`](https://github.com/NixOS/nixpkgs/branches/all
 [`*-small`](https://github.com/NixOS/nixpkgs/branches/all?query=-small) channel branches have passed a smaller test suite, which means they are more up-to-date with respect to their base branch, but offer fewer stability guarantees.
 
 :::{tip}
-Consult the [`nix-channel`](https://nixos.org/manual/nix/unstable/command-ref/nix-channel) entry in the Nix Reference Manual for more information on channels, and the [Nixpkgs contributing guide](https://github.com/NixOS/nixpkgs/blob/master/CONTRIBUTING.md#branch-conventions) on the Nixpkgs branching strategy.
+Consult the [`nix-channel`](https://nix.dev/manual/nix/2.22/command-ref/nix-channel) entry in the Nix Reference Manual for more information on channels, and the [Nixpkgs contributing guide](https://github.com/NixOS/nixpkgs/blob/master/CONTRIBUTING.md#branch-conventions) on the Nixpkgs branching strategy.
 :::
 
 ## Are there any impurities left in sandboxed builds?

source/tutorials/nix-language.md

@@ -953,7 +953,7 @@ Example:
 /nix/var/nix/profiles/per-user/root/channels/nixpkgs
 ```
 
-The value of a [lookup path](https://nixos.org/manual/nix/unstable/language/constructs/lookup-path) is a file system path that depends on the value of [`builtins.nixPath`](https://nixos.org/manual/nix/stable/language/builtin-constants#builtins-nixPath).
+The value of a [lookup path](https://nix.dev/manual/nix/2.22/language/constructs/lookup-path) is a file system path that depends on the value of [`builtins.nixPath`](https://nix.dev/manual/nix/2.22/language/builtin-constants#builtins-nixPath).
 
 In practice, `<nixpkgs>` points to the file system path of some revision of {term}`Nixpkgs`.