Update flake lock + fix consequences

After a flake lock update, some errors needed fixes:

- Updated Topiary input and formatted Nickel files
- Merging manual: remove line number-dependent part of the error
- Upgrade markdownlint config file to schema change
- Fix flake.nix

.markdownlint.json

@@ -5,6 +5,6 @@
         "tables": false
     },
     "MD024": {
-        "allow_different_nesting": true
+        "siblings_only": true
     }
 }

core/benches/arrays/fold.ncl

@@ -1,4 +1,5 @@
-let letter | Number -> std.string.Character = fun n =>
+let letter | Number -> std.string.Character
+  = fun n =>
     let letters = std.string.characters "abcdefghijklmnopqrstuvwxyz" in
     std.array.at (n % 26) letters
   in

core/benches/arrays/generate.ncl

@@ -10,7 +10,8 @@ let g = fun n => n * 2 + 5 in
     run = fun n => generate n g,
   },
   checked = {
-    generate_with_contract | forall a. Number -> (Number -> a) -> Array a = fun n g =>
+    generate_with_contract | forall a. Number -> (Number -> a) -> Array a
+      = fun n g =>
         if n == 0 then
           []
         else

core/stdlib/std.ncl

@@ -919,8 +919,7 @@
                   |> blame,
 
             # Outside of lazy data structures, we just use (==)
-            _ =>
-              fun ctr_label value =>
+            _ => fun ctr_label value =>
                 value
                 |> check_typeof_eq ctr_label
                 |> from_predicate ((==) constant) ctr_label,

doc/manual/merging.md

@@ -611,7 +611,6 @@ argument), we do get a contract violation error:
     { foo | FooContract }
     & { foo.required_field1 = "here" }
   in
- 
   intermediate
   & { foo.required_field2 = "here" }
   |> std.deep_seq intermediate
@@ -624,10 +623,7 @@ error: missing definition for `required_field2`
    8 │     & { foo.required_field1 = "here" }
      │             ------------------------ in this record
      │
-     ┌─ <stdlib/std.ncl>:3255:18
-     │
-3255 │     = fun x y => %deep_seq% x y,
-     │                  ------------ accessed here
+[...]
 ```
 
 #### Example

examples/arrays/arrays.ncl

@@ -3,15 +3,17 @@
 # Example array functions. This code is illustrative: prefer using the array
 # stdlib functions `std.array.map` and `std.array.fold_right` instead.
 let my_array_lib = {
-  map : forall a b. (a -> b) -> Array a -> Array b = fun f arr =>
+  map : forall a b. (a -> b) -> Array a -> Array b
+    = fun f arr =>
       if arr == [] then
         []
       else
         let head = std.array.first arr in
         let tail = std.array.drop_first arr in
         [f head] @ map f tail,
 
-  fold : forall a b. (a -> b -> b) -> b -> Array a -> b = fun f first arr =>
+  fold : forall a b. (a -> b -> b) -> b -> Array a -> b
+    = fun f first arr =>
       if arr == [] then
         first
       else

flake.nix

@@ -5,7 +5,6 @@
     pre-commit-hooks = {
       url = "github:cachix/pre-commit-hooks.nix";
       inputs.nixpkgs.follows = "nixpkgs";
-      inputs.flake-utils.follows = "flake-utils";
     };
     rust-overlay = {
       url = "github:oxalica/rust-overlay";
@@ -154,6 +153,7 @@
 
           markdownlint = {
             enable = true;
+            # settings.configuration = builtins.fromJSON (builtins.readFile ./.markdownlint.json);
             excludes = [
               "notes/(.+)\\.md$"
               "^RELEASES\\.md$"
@@ -394,13 +394,11 @@
                     inherit env;
                     CARGO_BUILD_TARGET = pkgs.rust.toRustTarget pkgs.pkgsMusl.stdenv.hostPlatform;
                     # For some reason, the rust build doesn't pick up the paths
-                    # to `libcxx` and `libcxxabi` from the stdenv. So we specify
-                    # them explicitly. Also, `libcxx` expects to be linked with
-                    # `libcxxabi` at the end, and we need to make the rust linker
-                    # aware of that.
+                    # to `libcxx`. So we specify them explicitly.
                     #
-                    # We also explicitly add `libc` because of https://github.com/rust-lang/rust/issues/89626.
-                    RUSTFLAGS = "-L${pkgs.pkgsMusl.llvmPackages.libcxx}/lib -L${pkgs.pkgsMusl.llvmPackages.libcxxabi}/lib -lstatic=c++abi -C link-arg=-lc";
+                    # We also explicitly add `libc` because of
+                    # https://github.com/rust-lang/rust/issues/89626.
+                    RUSTFLAGS = "-L${pkgs.pkgsMusl.llvmPackages.libcxx}/lib -lstatic=c++abi -C link-arg=-lc";
                     # Explain to `cc-rs` that it should use the `libcxx` C++
                     # standard library, and a static version of it, when building
                     # C++ libraries. The `cc-rs` crate is typically used in