flake.lock: Update

Locally disabled markdown-lint rules to make the CI pass, since the new
version wasn't happy with the current documentation anymore.

Flake lock file updates:

• Updated input 'flake-utils':
    'github:numtide/flake-utils/bee6a7250dd1b01844a2de7e02e4df7d8a0a206c' (2022-06-24)
  → 'github:numtide/flake-utils/c0e246b9b83f637f4681389ecabcb2681b4f3af0' (2022-08-07)
• Updated input 'nixpkgs':
    'github:NixOS/nixpkgs/6141b8932a5cf376fe18fcd368cecd9ad946cb68' (2022-06-23)
  → 'github:NixOS/nixpkgs/f3d0897be466aa09a37f6bf59e62c360c3f9a6cc' (2022-08-25)
• Updated input 'pre-commit-hooks':
    'github:cachix/pre-commit-hooks.nix/db3bd555d3a3ceab208bed48f983ccaa6a71a25e' (2022-06-25)
  → 'github:cachix/pre-commit-hooks.nix/8cb8ea5f1c7bc2984f460587fddd5f2e558f6eb8' (2022-08-18)
• Updated input 'rust-overlay':
    'github:oxalica/rust-overlay/59a3a304c987dc65d2a33de0a77a1ae6ae777cd4' (2022-06-25)
  → 'github:oxalica/rust-overlay/790c16639c7d8da8b36d0aa6a7c1f589af8c5f68' (2022-08-27)

RATIONALE.md

@@ -96,6 +96,8 @@ perks:
 
 #### Typing JSON
 
+<!-- markdownlint-disable MD051 -->
+
 The second motivation for a non fully static type system is that some code may
 be hard to type. JSON is a de-facto standard format for configuration and Nickel
 aims at being straightforwardly convertible to and from JSON. If it were to be
@@ -105,6 +107,8 @@ fully statically typed, it would have to type things like heterogeneous lists:
 of offering typing capabilities for common idioms, but when the type system
 falls short of expressivity, you can still write your code without types.
 
+<!-- markdownlint-enable MD051 -->
+
 #### Data validation
 
 Another peculiarity is that there is an external tool which will consume the

doc/manual/merging.md

@@ -28,6 +28,8 @@ the associated technical document [RFC001][rfc001].
 The section describes the behavior and use-cases of merge, by considering the
 following situations:
 
+<!-- markdownlint-disable MD051 -->
+
 - [Merging two records without common fields](#simple-merge-(no-common-fields))
 - [Merging records with common fields](#recursive-merge-(with-common-fields))
 - [Merging records with metadata](#merging-record-with-metadata)
@@ -36,6 +38,8 @@ following situations:
   - [Documentation](#documentation)
 - [Recursive overriding](#recursive-overriding)
 
+<!-- markdownlint-enable MD051 -->
+
 ## Simple merge (no common fields)
 
 Merging two records with no common fields results in a record with the fields