pre-commit: remove markdown-link-check hook

External link checkers are inherently flaky in CI due to
websites blocking automated requests (e.g. 403 errors).
Also remove JSON hooks (pretty-format-json, check-json)
since no JSON files remain in the repository.

Co-authored-by: Claude <noreply@anthropic.com>

.github/linters/mlc_config.json

@@ -1,26 +0,0 @@
-{
-  "retryOn429": true,
-  "retryCount": 3,
-  "aliveStatusCodes": [
-    200,
-    206,
-    502
-  ],
-  "ignorePatterns": [
-    {
-      "pattern": "^https://github.com/mruby/mruby/commit/"
-    },
-    {
-      "pattern": "^http://jp.rubyist.net/magazine/\\?0034-Enumerable_lz"
-    },
-    {
-      "pattern": "^https://ruby-doc.org/core-2.3.3"
-    },
-    {
-      "pattern": "^mailto:"
-    },
-    {
-      "pattern": "^https://www.iso.org/"
-    }
-  ]
-}

.pre-commit-config.yaml

@@ -55,9 +55,6 @@ repos:
       - id: check-executables-have-shebangs
         exclude: ^test/t/lang\.rb$
       - id: check-illegal-windows-names
-      - id: pretty-format-json
-        args: [--autofix, --no-sort-keys]
-      - id: check-json
       - id: check-merge-conflict
       - id: check-shebang-scripts-are-executable
       - id: check-vcs-permalinks
@@ -107,16 +104,6 @@ repos:
         args: [--config=.github/linters/.markdown-lint.yml]
         types: [markdown]
         files: \.md$
-  - repo: https://github.com/tcort/markdown-link-check
-    rev: v3.14.2
-    hooks:
-      - id: markdown-link-check
-        name: run markdown-link-check
-        description: checks hyperlinks in Markdown files
-        args: [--config=.github/linters/mlc_config.json, -q]
-        stages: [manual]
-        types: [markdown]
-        files: \.md$
   - repo: https://github.com/rubocop/rubocop
     rev: v1.81.7
     hooks: