local variables don't show up in completion

[karthiknadig]

Repro code:

from flake8.formatting.base import BaseFormatter
from xml.etree import ElementTree as ET

class Flake8formatter(BaseFormatter):
    def format(self, error):
        return '{0!r}'.format(error)
   
    def show_benchmarks(self, benchmarks):
        for benchmark, value in benchmarks:
            if ben
            testcase = ET.Element('benchmark')
            testcase.attrib['classname'] = 'flake8.benchmarks'
            testcase.attrib['name'] = benchmark
            testcase.attrib['value'] = value

[MikhailArkhipov]

Part of #693