Allow dev option of Composer require command via meta-data (front-matter)

[froschdesign]

The Composer require command is displayed on the start page of each documentation as installation command.
If a package is required for developing then the dev option can be added to the command on the start page.

This can be configured via a configuration entry in the mkdocs.yml file but it would be more intuitive to insert this directly into the related file.

Current Usage

mkdocs.yml:

extra:
    project: Components
    installation:
        composer_dev: true

https://github.com/laminas/laminas-coding-standard/blob/bcf6e07fe4690240be7beb6d884d0b0fafa6a251/mkdocs.yml#L9-L10

Preferred Usage

index.md:

---
installation:
    composer_dev: true
---

# Example

…

https://www.mkdocs.org/user-guide/writing-your-docs/#meta-data

Example

https://docs.laminas.dev/laminas-coding-standard/#installation