remove duplicated line in docs

[beautytiger]

What this PR does / why we need it:
cleanup docs, remove duplicated line

Which issue this PR fixes (optional, in fixes #<issue number>(, fixes #<issue_number>, ...) format, will close that issue when PR gets merged): fixes #

Special notes for your reviewer:

[k8s-ci-robot]

Hi @beautytiger. Thanks for your PR.

I'm waiting for a kubernetes member to verify that this patch is reasonable to test. If it is, they should reply with /ok-to-test on its own line. Until that is done, I will not automatically test new commits in this PR, but the usual testing commands by org members will still work. Regular contributors should join the org to skip this step.

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[aledbf]

/ok-to-test

[codecov-io]

Codecov Report

Merging #4623 into master will increase coverage by 0.02%.
The diff coverage is n/a.

@@            Coverage Diff            @@
##           master   #4623      +/-   ##
=========================================
+ Coverage   58.67%   58.7%   +0.02%     
=========================================
  Files          88      88              
  Lines        6764    6764              
=========================================
+ Hits         3969    3971       +2     
+ Misses       2356    2355       -1     
+ Partials      439     438       -1

Impacted Files	Coverage Δ
internal/ingress/metric/collectors/process.go	90.42% <0%> (+2.12%)	⬆️

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[aledbf]

/lgtm

[aledbf]

@beautytiger thanks!

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: aledbf, beautytiger

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