Typing improvements for some core components

[wRAR]

No description provided.

[codecov]

Codecov Report

Merging #5889 (9638c57) into master (96033ce) will decrease coverage by 0.03%.
The diff coverage is 94.38%.

❗ Current head 9638c57 differs from pull request most recent head 81a5b71. Consider uploading reports for the commit 81a5b71 to get more accurate results

@@            Coverage Diff             @@
##           master    #5889      +/-   ##
==========================================
- Coverage   88.85%   88.82%   -0.03%     
==========================================
  Files         162      162              
  Lines       11057    11101      +44     
  Branches     1801     1804       +3     
==========================================
+ Hits         9825     9861      +36     
- Misses        954      959       +5     
- Partials      278      281       +3     

Impacted Files	Coverage Δ
scrapy/utils/misc.py	96.52% <60.00%> (-1.35%)	⬇️
scrapy/signalmanager.py	81.81% <83.33%> (+1.81%)	⬆️
scrapy/core/engine.py	83.68% <90.90%> (-0.51%)	⬇️
scrapy/statscollectors.py	89.28% <92.85%> (-2.88%)	⬇️
scrapy/core/scheduler.py	93.23% <93.75%> (-0.52%)	⬇️
scrapy/core/downloader/__init__.py	92.80% <100.00%> (+0.05%)	⬆️
scrapy/core/scraper.py	84.94% <100.00%> (+0.33%)	⬆️
scrapy/core/spidermw.py	99.44% <100.00%> (+<0.01%)	⬆️
scrapy/crawler.py	87.30% <100.00%> (+0.13%)	⬆️
scrapy/exceptions.py	100.00% <100.00%> (ø)
... and 6 more