Fix: typo of file and func name

[Flying-Tom]

What type of PR is this?

/kind bug

What this PR does / why we need it:

Some typo found:

• pkg/plugin/prometheus/pulgin.go
• Render method name of some plugins of fleet-manager

Which issue(s) this PR fixes:
Fixes #

Special notes for your reviewer:

Does this PR introduce a user-facing change?:

NONE

[kurator-bot]

Welcome @Flying-Tom! It looks like this is your first PR to kurator-dev/kurator 🎉

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[zirain]

/lgtm

[hzxuzhonghu]

Thank you

[hzxuzhonghu]

Please fix DCO,
In your local branch, run: git rebase HEAD~2 --signoff
Force push your changes to overwrite the branch: git push --force-with-lease origin typo-fix

[zirain]

/approve

[kurator-bot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: hzxuzhonghu, zirain

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[zirain]

/lgtm