modernize code formatting

[garlick]

Problem: some older code violates RFC 7 whitespace guidelines.

Break long parameter lists to one per line.

This chunk of whitespace cleanup was peeled off of #6467

[grondo]

Nice cleanup!

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 83.57%. Comparing base (0cfb291) to head (a288986).
Report is 2 commits behind head on master.

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #6481      +/-   ##
==========================================
- Coverage   83.58%   83.57%   -0.01%     
==========================================
  Files         524      524              
  Lines       87611    87617       +6     
==========================================
+ Hits        73227    73229       +2     
- Misses      14384    14388       +4     

Files with missing lines	Coverage Δ
src/common/libflux/conf.c	85.56% <100.00%> (ø)
src/common/libflux/event.c	77.66% <100.00%> (ø)
src/common/libflux/fripp.c	88.25% <100.00%> (+0.04%)	⬆️
src/common/libflux/future.c	88.77% <100.00%> (ø)
src/common/libflux/message.c	91.91% <ø> (ø)
src/common/libflux/msg_handler.c	86.54% <ø> (ø)
src/common/libflux/plugin.c	92.50% <100.00%> (+0.02%)	⬆️
src/common/libflux/request.c	84.76% <100.00%> (ø)
src/common/libflux/service.c	60.00% <100.00%> (ø)
src/common/libkvs/kvs_dir.c	88.88% <100.00%> (+0.33%)	⬆️
... and 1 more

... and 9 files with indirect coverage changes