fix wrong spells in coredns-007.md

[AllenZMC]

1. Why is this pull request needed and what does it do?

Make the comment more readable

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[codecov-io]

Codecov Report

Merging #3142 into master will increase coverage by 0.04%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master    #3142      +/-   ##
==========================================
+ Coverage   55.73%   55.78%   +0.04%     
==========================================
  Files         210      210              
  Lines       10516    10516              
==========================================
+ Hits         5861     5866       +5     
+ Misses       4229     4226       -3     
+ Partials      426      424       -2

Impacted Files	Coverage Δ
plugin/route53/route53.go	86.61% <0%> (+2.11%)	⬆️
plugin/file/reload.go	74.28% <0%> (+5.71%)	⬆️

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