FIX: Select function in segmentation resampling workflow

[mgxd]

The segmentation selection code was a bit convoluted, this addresses the following:

• Adding a mapping for common replacements
• Avoiding string iteration
• Stopping iteration over files upon the first match
• Raising FileNotFoundError, rather than an unclear IndexError, if no matches are found.

[codecov]

Codecov Report

Attention: Patch coverage is 93.75000% with 1 line in your changes missing coverage. Please review.

Project coverage is 66.71%. Comparing base (f368a28) to head (4738420).
Report is 6 commits behind head on master.

Files	Patch %	Lines
smriprep/workflows/surfaces.py	91.66%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master     #450      +/-   ##
==========================================
+ Coverage   66.36%   66.71%   +0.35%     
==========================================
  Files          31       31              
  Lines        2072     2076       +4     
  Branches      249      246       -3     
==========================================
+ Hits         1375     1385      +10     
+ Misses        696      690       -6     
  Partials        1        1              

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[mgxd]

@effigies can we sneak this into a patch release, or will it require a new minor?

[effigies]

I'm okay with a patch release. The workflow cache invalidation is straightforward here.