Flake8: remove E126

[elacuesta]

Continuation line over-indented for hanging indent

Based on #4542 to avoid merge conflicts. (merged)

[codecov]

Codecov Report

Merging #4543 into master will decrease coverage by 0.00%.
The diff coverage is 90.90%.

@@            Coverage Diff             @@
##           master    #4543      +/-   ##
==========================================
- Coverage   84.50%   84.50%   -0.01%     
==========================================
  Files         164      164              
  Lines        9903     9904       +1     
  Branches     1481     1482       +1     
==========================================
  Hits         8369     8369              
  Misses       1266     1266              
- Partials      268      269       +1     

Impacted Files	Coverage Δ
scrapy/core/downloader/contextfactory.py	96.66% <0.00%> (ø)
scrapy/core/downloader/handlers/s3.py	65.67% <ø> (ø)
scrapy/core/downloader/webclient.py	97.95% <ø> (ø)
scrapy/downloadermiddlewares/retry.py	100.00% <100.00%> (ø)
scrapy/spiderloader.py	100.00% <100.00%> (ø)
scrapy/utils/trackref.py	82.85% <0.00%> (-2.86%)	⬇️