Lines in options files with only spaces are now ignored, and text of first line with error is printed

[jajhall]

I found it irritating that an options file with a line containing only spaces caused an error

Such lines are now skipped, and if an error occurs (elsewhere) the text of the line is now logged, as well as the line number

[jajhall]

Changes to pdhg.cpp are due to me running clang-format on it. No reason why clang-format CI shouldn't include HiPDLP

[jajhall]

This closes #3049

[codecov]

Codecov Report

❌ Patch coverage is 83.33333% with 3 lines in your changes missing coverage. Please review.
✅ Project coverage is 72.94%. Comparing base (355e646) to head (7ac997f).
⚠️ Report is 1 commits behind head on latest.

Files with missing lines	Patch %	Lines
highs/pdlp/hipdlp/pdhg.cc	0.00%	3 Missing ⚠️

Additional details and impacted files

@@           Coverage Diff           @@
##           latest    #3057   +/-   ##
=======================================
  Coverage   72.93%   72.94%           
=======================================
  Files         426      426           
  Lines      102183   102198   +15     
  Branches    16444    16443    -1     
=======================================
+ Hits        74529    74547   +18     
+ Misses      27378    27375    -3     
  Partials      276      276           

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[galabovaa]

Looks good to me!