etc: add more known hashes

This should be less of an issue as of DetSys' nix-installer 0.15.0 which
no longer includes the version number in `nix.conf`.

doc/known-files/97f4135d262ca22d65c9554aad795c10a4491fa61b67d9c2430f4d82bbfec9a2

@@ -0,0 +1,8 @@
+# Generated by https://github.com/DeterminateSystems/nix-installer.
+# See `/nix/nix-installer --version` for the version details.
+
+build-users-group = nixbld
+experimental-features = nix-command flakes repl-flake
+bash-prompt-prefix = (nix:$name)\040
+max-jobs = auto
+extra-nix-path = nixpkgs=flake:nixpkgs

doc/known-files/c6080216f2a170611e339c3f46e4e1d61aaf0d8b417ad93ade8d647da1382c11

@@ -0,0 +1,6 @@
+# Generated by https://github.com/DeterminateSystems/nix-installer, version 0.14.0.
+build-users-group = nixbld
+experimental-features = nix-command flakes repl-flake
+bash-prompt-prefix = (nix:$name)\040
+max-jobs = auto
+extra-nix-path = nixpkgs=flake:nixpkgs

modules/nix/default.nix

@@ -671,6 +671,8 @@ in
       "c06b0c6080dd1d62e61a30cfad100c0cfed2d3bcd378e296632dc3b28b31dc69"  # official Nix installer as of 2.0.1
       "ff08c12813680da98c4240328f828647b67a65ba7aa89c022bd8072cba862cf1"  # official Nix installer as of 2.4
       "f3e03d851c240c1aa7daccd144ee929f0f5971982424c868c434eb6030e961d4"  # DeterminateSystems Nix installer 0.10.0
+      "c6080216f2a170611e339c3f46e4e1d61aaf0d8b417ad93ade8d647da1382c11"  # DeterminateSystems Nix installer 0.14.0
+      "97f4135d262ca22d65c9554aad795c10a4491fa61b67d9c2430f4d82bbfec9a2"  # DeterminateSystems Nix installer 0.15.1+
     ];
 
     environment.etc."nix/registry.json".text = builtins.toJSON {