docs(pre-commit): fix pre-commit YAML style (#8146)

docs/pre-commit-hooks.md

@@ -71,7 +71,7 @@ console:
 
 ```yaml
 hooks:
-  - id: poetry-export
+-   id: poetry-export
     args: ["-f", "requirements.txt"]
     verbose: true
 ```
@@ -80,7 +80,7 @@ Also, `--dev` can be added to `args` to write dev-dependencies to `requirements.
 
 ```yaml
 hooks:
-  - id: poetry-export
+-   id: poetry-export
     args: ["--dev", "-f", "requirements.txt", "-o", "requirements.txt"]
 ```
 
@@ -93,7 +93,7 @@ A full `.pre-commit-config.yaml` example:
 
 ```yaml
 repos:
-  - repo: https://github.com/python-poetry/poetry
+-   repo: https://github.com/python-poetry/poetry
     rev: ''  # add version here
     hooks:
     -   id: poetry-check