So there is a blank line after the signature that gets automatically embedded.  For instance, inspecting `merge_with` in IPython gives:
```python
In [17]: cytoolz.merge_with?
Type:        builtin_function_or_method
String form: <built-in function merge_with>
Docstring:
merge_with(func, *dicts)

Merge dictionaries and apply function to combined values

A key may occur in more than one dict, and all values mapped from the key
will be passed to the function as a list, such as func([val1, val2, ...]).

>>> merge_with(sum, {1: 1, 2: 2}, {1: 10, 2: 20})
{1: 11, 2: 22}

>>> merge_with(first, {1: 1, 2: 2}, {2: 20, 3: 30})  # doctest: +SKIP
{1: 1, 2: 2, 3: 30}

See Also:
    merge
```
Without the new newline, the docstring would begin:
```python
Docstring:
merge_with(func, *dicts)
Merge dictionaries and apply function to combined values
```
which I find less readable.

Unless you prefer the aesthetics of having a newline at the beginning of a doc string (which is okay to do, because Python's `help` and IPython's `?` chomps extra whitespace), there really isn't a reason to do this in `toolz` too other than trying to have similar conventions for `toolz` and `cytoolz`.