chore: type alias typo

[fengjiachun]

I hereby agree to the terms of the GreptimeDB CLA

What's changed and what's your intention?

As the title said.

Checklist

• I have written the necessary rustdoc comments.
• I have added the necessary unit tests and integration tests.

Refer to a related PR or issue link (optional)

[codecov]

Codecov Report

Merging #2452 (87b2ac4) into develop (ca50ba5) will decrease coverage by 0.06%.
Report is 1 commits behind head on develop.
The diff coverage is n/a.

Additional details and impacted files

@@             Coverage Diff             @@
##           develop    #2452      +/-   ##
===========================================
- Coverage    77.58%   77.53%   -0.06%     
===========================================
  Files          717      717              
  Lines       112751   112751              
===========================================
- Hits         87474    87417      -57     
- Misses       25277    25334      +57