Flake8: Remove E128

[elacuesta]

Continuation line under-indented for visual indent

Such a big PR for only one code, sorry 😓

Based on #4543 to avoid merge conflicts merged

[codecov]

Codecov Report

Merging #4545 into master will decrease coverage by 0.00%.
The diff coverage is 92.85%.

@@            Coverage Diff             @@
##           master    #4545      +/-   ##
==========================================
- Coverage   84.55%   84.55%   -0.01%     
==========================================
  Files         164      164              
  Lines        9922     9923       +1     
  Branches     1475     1475              
==========================================
  Hits         8390     8390              
  Misses       1266     1266              
- Partials      266      267       +1     

Impacted Files	Coverage Δ
scrapy/commands/__init__.py	61.11% <ø> (ø)
scrapy/commands/genspider.py	83.72% <ø> (ø)
scrapy/commands/parse.py	20.21% <ø> (ø)
scrapy/commands/settings.py	71.87% <ø> (ø)
scrapy/commands/version.py	100.00% <ø> (ø)
scrapy/mail.py	73.75% <50.00%> (ø)
scrapy/commands/fetch.py	89.13% <100.00%> (ø)
scrapy/commands/shell.py	92.85% <100.00%> (ø)
scrapy/commands/startproject.py	100.00% <100.00%> (ø)
scrapy/core/downloader/contextfactory.py	96.66% <100.00%> (ø)
... and 11 more

[wRAR]

@elacuesta there are conflicts here as well