Clang format not correctly applied to C files

[dqii]

SOURCES in the file() function does not expand. It will try to find a file or directory literally named by the value of ${SOURCES} which is not desired.

[codecov]

Codecov Report

Merging #115 (f8f8926) into main (4646afc) will decrease coverage by 0.33%.
The diff coverage is 80.00%.

❗ Current head f8f8926 differs from pull request most recent head cbd8fd8. Consider uploading reports for the commit cbd8fd8 to get more accurate results

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #115      +/-   ##
==========================================
- Coverage   84.28%   83.96%   -0.33%     
==========================================
  Files          13       13              
  Lines        1069      979      -90     
  Branches      238      194      -44     
==========================================
- Hits          901      822      -79     
+ Misses         74       68       -6     
+ Partials       94       89       -5     

Files Changed	Coverage Δ
src/hnsw/extra_dirtied.c	85.71% <ø> (ø)
src/hnsw.c	83.14% <76.92%> (ø)
src/hnsw/insert.c	80.70% <100.00%> (ø)

... and 7 files with indirect coverage changes