Update fixture.rst

[oleg-yegorov]

add a missing import

[asottile]

thanks!

[codecov]

Codecov Report

Merging #5295 into master will increase coverage by 2.56%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master    #5295      +/-   ##
==========================================
+ Coverage   91.45%   94.01%   +2.56%     
==========================================
  Files         115      115              
  Lines       26165    26165              
  Branches     2578     2578              
==========================================
+ Hits        23928    24598     +670     
+ Misses       1916     1253     -663     
+ Partials      321      314       -7

Impacted Files	Coverage Δ
testing/python/collect.py	75.69% <0%> (-23.25%)	⬇️
testing/python/show_fixtures_per_test.py	85.29% <0%> (-14.71%)	⬇️
testing/test_terminal.py	88.02% <0%> (-10.11%)	⬇️
testing/python/raises.py	88.51% <0%> (-6.09%)	⬇️
src/_pytest/terminal.py	91.21% <0%> (-2.24%)	⬇️
src/_pytest/compat.py	95.97% <0%> (-1.01%)	⬇️
src/_pytest/python.py	92.73% <0%> (-0.37%)	⬇️
src/_pytest/fixtures.py	97.93% <0%> (+0.13%)	⬆️
testing/python/metafunc.py	92.27% <0%> (+0.36%)	⬆️
src/_pytest/runner.py	98.01% <0%> (+1.19%)	⬆️
... and 13 more

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update 6663cb0...c5fa1d1. Read the comment docs.