Sort the builtins.fetchTree doc's lists

This makes the output easier to compare with the new machine-generated
lists in NixOS#9732.

The hand-curated order did have the advantage of putting more important
attributes at the top, but I don't think it is worth preserving that
when `std::map` is so much easier to work with. The right solution to
leading the reader to the more important attributes is to call them out
in the intro texts.

Author: Ericson2314

src/libexpr/primops/fetchTree.cc

@@ -317,43 +317,33 @@ static RegisterPrimOp primop_fetchTree({
             > }
             > ```
 
-      - `"tarball"`
+      - `"git"`
 
-        Download a tar archive and extract it into the Nix store.
-        This has the same underlying implementation as [`builtins.fetchTarball`](@docroot@/language/builtins.md#builtins-fetchTarball)
+        Fetch a Git tree and copy it to the Nix store.
+        This is similar to [`builtins.fetchGit`](@docroot@/language/builtins.md#builtins-fetchGit).
 
-        - `url` (String, required)
+        - `allRefs` (Bool, optional)
 
-           > **Example**
-           >
-           > ```nix
-           > fetchTree {
-           >   type = "tarball";
-           >   url = "https://github.com/NixOS/nixpkgs/tarball/nixpkgs-23.11";
-           > }
-           > ```
+          By default, this has no effect. This becomes relevant only once `shallow` cloning is disabled.
 
-      - `"git"`
+          Whether to fetch all references (eg. branches and tags) of the repository.
+          With this argument being true, it's possible to load a `rev` from *any* `ref`.
+          (Without setting this option, only `rev`s from the specified `ref` are supported).
 
-        Fetch a Git tree and copy it to the Nix store.
-        This is similar to [`builtins.fetchGit`](@docroot@/language/builtins.md#builtins-fetchGit).
+          Default: `false`
 
-        - `url` (String, required)
+        - `lastModified` (Integer, optional)
 
-          The URL formats supported are the same as for Git itself.
+          Unix timestamp of the fetched commit.
 
-          > **Example**
-          >
-          > ```nix
-          > fetchTree {
-          >   type = "git";
-          >   url = "[email protected]:NixOS/nixpkgs.git";
-          > }
-          > ```
+          If set, pass through the value to the output attribute set.
+          Otherwise, generated from the fetched Git tree.
 
-          > **Note**
-          >
-          > If the URL points to a local directory, and no `ref` or `rev` is given, Nix only considers files added to the Git index, as listed by `git ls-files` but use the *current file contents* of the Git working directory.
+        - `lfs` (Bool, optional)
+
+          Fetch any [Git LFS](https://git-lfs.com/) files.
+
+          Default: `false`
 
         - `ref` (String, optional)
 
@@ -369,6 +359,13 @@ static RegisterPrimOp primop_fetchTree({
 
           Default: the tip of `ref`
 
+        - `revCount` (Integer, optional)
+
+          Number of revisions in the history of the Git repository before the fetched commit.
+
+          If set, pass through the value to the output attribute set.
+          Otherwise, generated from the fetched Git tree.
+
         - `shallow` (Bool, optional)
 
           Make a shallow clone when fetching the Git tree.
@@ -382,35 +379,38 @@ static RegisterPrimOp primop_fetchTree({
 
           Default: `false`
 
-        - `lfs` (Bool, optional)
-
-          Fetch any [Git LFS](https://git-lfs.com/) files.
-
-          Default: `false`
-
-        - `allRefs` (Bool, optional)
-
-          By default, this has no effect. This becomes relevant only once `shallow` cloning is disabled.
-
-          Whether to fetch all references (eg. branches and tags) of the repository.
-          With this argument being true, it's possible to load a `rev` from *any* `ref`.
-          (Without setting this option, only `rev`s from the specified `ref` are supported).
+        - `url` (String, required)
 
-          Default: `false`
+          The URL formats supported are the same as for Git itself.
 
-        - `lastModified` (Integer, optional)
+          > **Example**
+          >
+          > ```nix
+          > fetchTree {
+          >   type = "git";
+          >   url = "[email protected]:NixOS/nixpkgs.git";
+          > }
+          > ```
 
-          Unix timestamp of the fetched commit.
+          > **Note**
+          >
+          > If the URL points to a local directory, and no `ref` or `rev` is given, Nix only considers files added to the Git index, as listed by `git ls-files` but use the *current file contents* of the Git working directory.
 
-          If set, pass through the value to the output attribute set.
-          Otherwise, generated from the fetched Git tree.
+      - `"tarball"`
 
-        - `revCount` (Integer, optional)
+        Download a tar archive and extract it into the Nix store.
+        This has the same underlying implementation as [`builtins.fetchTarball`](@docroot@/language/builtins.md#builtins-fetchTarball)
 
-          Number of revisions in the history of the Git repository before the fetched commit.
+        - `url` (String, required)
 
-          If set, pass through the value to the output attribute set.
-          Otherwise, generated from the fetched Git tree.
+           > **Example**
+           >
+           > ```nix
+           > fetchTree {
+           >   type = "tarball";
+           >   url = "https://github.com/NixOS/nixpkgs/tarball/nixpkgs-23.11";
+           > }
+           > ```
 
       The following input types are still subject to change: