Add placeholder slot

[TotomInc]

Currently, we don't have the possibility to add a custom placeholder content except from the props.placeholder property.

Add a placeholder slot, ensure to put it inside slots.ts. Add test(s) to ensure the placeholder slot content is working as expected.

[nats-afs]

Actualmente trabajo como desarrollador fullstack, utilizando Laravel en el backend, Vue en el frontend y React Native para desarrollo móvil. Estoy acostumbrado a trabajar con tecnologías modernas y enfrentar desafíos técnicos a diario. Me interesó esta issue porque representa una excelente oportunidad para aportar desde mi experiencia y comenzar a contribuir activamente al proyecto. Me gustan los retos y estoy comprometido con entregar soluciones de calidad.

[nats-afs]

I currently work as a fullstack developer, using Laravel for the backend, Vue for the frontend, and React Native for mobile development. I'm used to working with modern technologies and tackling technical challenges on a daily basis. This issue caught my attention as a great opportunity to contribute my experience and start actively collaborating with the project. I enjoy challenges and I'm committed to delivering high-quality solutions.

On English

[TotomInc]

Hi @nats-afs, feel free to work on the issue and create a pull-request