[pre-commit.ci] pre-commit autoupdate

updates:
- [github.com/adamchainz/blacken-docs: 1.16.0 → 1.18.0](adamchainz/blacken-docs@1.16.0...1.18.0)

.pre-commit-config.yaml

@@ -28,7 +28,7 @@ repos:
       args: [--jobs=1]
       types: [rst]
   - repo: https://github.com/adamchainz/blacken-docs
-    rev: "1.16.0"
+    rev: "1.18.0"
     hooks:
     - id: blacken-docs
       args: [--line-length=79]