Update README to make pip install copy-pastable on zsh

[uglide]

Make pip install redis[hiredis] copy-pastable on zsh

Fix #2445

Pull Request check-list

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• Does $ tox pass with this change (including linting)?
• Do the CI tests pass with this change (enable it first in your forked repo and wait for the github action build to finish)?
• Is the new or changed code fully tested?
• Is a documentation update included (if this change modifies existing APIs, or introduces new ones)?
• Is there an example added to the examples folder (if applicable)?
• Was the change added to CHANGES file?

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afterwards / while the PR is open.

Description of change

Please provide a description of the change here.

[codecov-commenter]

Codecov Report

Base: 92.28% // Head: 92.28% // Increases project coverage by +0.00% 🎉

Coverage data is based on head (1af47cc) compared to base (5cb5712).
Patch has no changes to coverable lines.

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Additional details and impacted files

@@           Coverage Diff           @@
##           master    #2584   +/-   ##
=======================================
  Coverage   92.28%   92.28%           
=======================================
  Files         115      115           
  Lines       29736    29736           
=======================================
+ Hits        27442    27443    +1     
+ Misses       2294     2293    -1     

Impacted Files	Coverage Δ
tests/test_asyncio/test_search.py	98.29% <0.00%> (-0.35%)	⬇️
tests/test_cluster.py	96.97% <0.00%> (+0.10%)	⬆️
tests/test_asyncio/test_pubsub.py	99.53% <0.00%> (+0.15%)	⬆️

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