arrow

ARROW-10316: [Python] Improve introspection of compute function options

Generate a signature for compute functions that better reflects the accepted arguments.

Example before:
```python
>>> pc.sum?
Signature: pc.sum(array, *, options=None, memory_pool=None, **kwargs)
Docstring:
Compute the sum of a numeric array.
[...]
```

Same example after:
```python
>>> ?pc.sum
Signature:
pc.sum(
    array,
    *,
    memory_pool=None,
    options=None,
    skip_nulls=True,
    min_count=1,
)
Docstring:
Compute the sum of a numeric array.
[...]
```

One caveat is that the individual options are not explicitly documented (yet):
```
Parameters
----------
array : Array-like
    Argument to compute function
memory_pool : pyarrow.MemoryPool, optional
    If not passed, will allocate memory from the default memory pool.
options : pyarrow.compute.ScalarAggregateOptions, optional
    Parameters altering compute function semantics
**kwargs : optional
    Parameters for ScalarAggregateOptions constructor. Either `options`
    or `**kwargs` can be passed, but not both at the same time.
```

Closes #10581 from pitrou/ARROW-10316-wrapped-compute-func

Authored-by: Antoine Pitrou <antoine@python.org>
Signed-off-by: Antoine Pitrou <antoine@python.org>