fix(codes/c): Fix bubble_sort.c

[Gonglja]

If this PR is related to coding or code translation, please fill out the checklist and paste the console outputs to the PR.

• I've tested the code and ensured the outputs are the same as the outputs of reference code.
• I've checked the code (formatting, comments, indentation, file header, etc) carefully.
• The code does not rely on a particular environment or IDE and can be executed on a standard system (Win, macOS, Ubuntu).

[Gonglja]

#60 (comment)

[krahets]

Thanks for the fix!