A dynamic family

>>> [!note] Informations
**dyn*a***
**dyn*b***
This family builds families dynamically.
`standard`
**Identifiers**:
- a
- b >>> | Variable | Description | |--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|--------------------------------------------------------| | **dyn*a*.var**
**dyn*b*.var**
[`string`](https://rougail.readthedocs.io/en/latest/variable.html#variables-types) `standard` `mandatory` | A variable inside dynamic family.
**Default**: val |