More edge cases for completion: lambdas and `async` functions

[krassowski]

With

%config Completer.use_jedi=True

We should be able to complete on lambda results e.g.:

"\n".join(
    [
        "make_list = lambda: []",
        "make_list().",
    ]
),

often lambda will be used for deferred if/else like lambda number: "odd" if x % 2 == 1 else "even"

Async functions - this should complete coroutine methods e.g. .close():

"\n".join(
    [
        "async def async_func():",
        "    return []",
        "async_func().",
    ]
),

(await async_func()). should complete the potential return value methods.

Both are supported by jedi.

[krassowski]

Hmm it looks like things inside loops do not work well either.

For full async support we would potentially want to support:

import asyncio

async def async_range():
    for i in range(10):
        yield i
        await asyncio.sleep(0.1)

async for i in async_range(10):
    i.<tab>

but currently completions on objects defined in for loops is not implemented:

for i in range(10):
    i.<tab>

And surprisingly even this does not work, even though it should:

i = 10
white True:
    i.<tab>