fix(documentation): Fix some typos

[alfirin]

Fix some word typos

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[k8s-reviewable]

This change is 

[alfirin]

I just signed the cla/linuxfoundation !

[coveralls]

Coverage remained the same at 33.473% when pulling d1e955c on alfirin:patch-1 into 132caff on kubernetes:master.

[aledbf]

/lgtm

[aledbf]

@alfirin thanks!