chore: remove repetitive words

[gcmutator]

I hereby agree to the terms of the GreptimeDB CLA.

Refer to a related PR or issue link (optional)

What's changed and what's your intention?

TRIVIAL AS IS

Checklist

• I have written the necessary rustdoc comments.
• I have added the necessary unit tests and integration tests.
• This PR does not require documentation updates.

[tisonkun]

Thank you!

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 85.07%. Comparing base (aeca0d8) to head (bd89dfa).

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #3469      +/-   ##
==========================================
- Coverage   85.50%   85.07%   -0.43%     
==========================================
  Files         896      896              
  Lines      147546   147546              
==========================================
- Hits       126153   125531     -622     
- Misses      21393    22015     +622