Fix escaping of integer indexes with multiple backslashes

[isidentical]

Resolves #1285

[codecov-commenter]

Codecov Report

Merging #1288 (8147f40) into master (4d7d6b6) will decrease coverage by 0.74%.
The diff coverage is 95.09%.

@@            Coverage Diff             @@
##           master    #1288      +/-   ##
==========================================
- Coverage   97.28%   96.53%   -0.75%     
==========================================
  Files          67       85      +18     
  Lines        4235     5975    +1740     
==========================================
+ Hits         4120     5768    +1648     
- Misses        115      207      +92     

Impacted Files	Coverage Δ
tests/test_binary.py	100.00% <ø> (ø)
httpie/compat.py	31.11% <27.90%> (-68.89%)	⬇️
tests/conftest.py	77.14% <58.33%> (-9.82%)	⬇️
httpie/output/lexers/http.py	59.09% <59.09%> (ø)
tests/test_ssl.py	91.01% <66.66%> (-3.93%)	⬇️
httpie/manager/__main__.py	82.35% <82.35%> (ø)
httpie/output/lexers/metadata.py	82.35% <82.35%> (ø)
httpie/models.py	94.23% <90.00%> (-3.14%)	⬇️
tests/test_uploads.py	97.66% <92.15%> (-2.34%)	⬇️
httpie/manager/core.py	92.85% <92.85%> (ø)
... and 71 more

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[jkbrzt]

Great fix! I think this deserves a mention in CHANGELOG.md.

[isidentical]

@jakubroztocil I think we already do (if I am not missing anything).

[isidentical]

https://github.com/httpie/httpie/blob/master/CHANGELOG.md

[jkbrzt]

Sorry, yes, we do!