automatically generate a documentation of all configurables?

Hi guys,

First of all, I really like your work! 👏. I have a question regarding documentation and transparency. If I have multiple places in my code that use `@gin.configurable`, can I somehow aggregate all those places and maybe even generate (Sphinx) documentation out of it?

Example:
```python
@gin.configurable
def fun_a(param_a: str, param_b: bool = False, param_c: Sequence[int] = (1, 2, 3)):
"""some docstring that even describes the parameters"""
pass

@gin.configurable
def fun_b(param_a: float = 1.0):
pass
```

Can I get output like
```
Configurables:

fun_a
param_a: string
I am parameter A.
param_b: bool, default `False`
I am parameter B.
param_c: Sequence of integers, default `(1, 2, 3)`
I am parameter A.

fun_b
param_a: float, default 1.0
I am parameter A.
```
maybe even in machine readable format that anything could read and further process.