Fixing some typos in user guide

[didier-durand]

Hi there,
fixing some typos in user guide
best,
Didier

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[didier-durand]

/assign @irfanurrehman

[hectorj2f]

/approve

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: didier-durand, hectorj2f

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[hectorj2f]

/lgtm

[hectorj2f]

Thanks @didier-durand

[didier-durand]

@hectorj2f : Hector, you're welcome: my pleasure to contribute. Didier