catch RuntimeError and raise custom exception for xyxymatch error

[braingram]

This PR catches the RuntimeError raised by xyxymatch when multiple reference sources match a single source and raises a custom exception.

This change is motivated by the error handling code in jwst and romancal which inspect the error message and can be simplified once the changes in this PR are released.

See the below linked issue for details and why this change is being made in tweakwcs instead of xyxymatch

Closes spacetelescope/stsci.stimage#33

[codecov]

Codecov Report

Attention: Patch coverage is 88.88889% with 1 line in your changes missing coverage. Please review.

Project coverage is 93.74%. Comparing base (fd5641c) to head (f91c66b).
Report is 13 commits behind head on main.

Files	Patch %	Lines
tweakwcs/matchutils.py	88.88%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #204      +/-   ##
==========================================
- Coverage   93.77%   93.74%   -0.03%     
==========================================
  Files          11       11              
  Lines        1992     1999       +7     
==========================================
+ Hits         1868     1874       +6     
- Misses        124      125       +1     

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[braingram]

Thanks for the review and suggestions. I included them in the most recent commits.