Mark the nix CLI as *the* interface in the manual, deprecate nix-*

doc/manual/source/SUMMARY.md.in

@@ -54,7 +54,9 @@
 - [Command Reference](command-ref/index.md)
   - [Common Options](command-ref/opt-common.md)
   - [Common Environment Variables](command-ref/env-common.md)
-  - [Main Commands](command-ref/main-commands.md)
+  - [Subcommands](command-ref/subcommands.md)
+{{#include ./command-ref/new-cli/SUMMARY.md}}
+  - [Deprecated Commands](command-ref/main-commands.md)
     - [nix-build](command-ref/nix-build.md)
     - [nix-shell](command-ref/nix-shell.md)
     - [nix-store](command-ref/nix-store.md)
@@ -98,8 +100,6 @@
     - [nix-hash](command-ref/nix-hash.md)
     - [nix-instantiate](command-ref/nix-instantiate.md)
     - [nix-prefetch-url](command-ref/nix-prefetch-url.md)
-  - [Experimental Commands](command-ref/experimental-commands.md)
-{{#include ./command-ref/new-cli/SUMMARY.md}}
   - [Files](command-ref/files.md)
     - [nix.conf](command-ref/conf-file.md)
     - [Profiles](command-ref/files/profiles.md)

doc/manual/source/command-ref/experimental-commands.md

@@ -1,8 +0,0 @@
-# Experimental Commands
-
-This section lists [experimental commands](@docroot@/development/experimental-features.md#xp-feature-nix-command).
-
-> **Warning**
->
-> These commands may be removed in the future, or their syntax may
-> change in incompatible ways.

doc/manual/source/command-ref/subcommands.md

@@ -0,0 +1,3 @@
+# Subcommands
+
+This section lists all the subcommands of the `nix` CLI.