Fix BIDSPath partially matching a value

[PierreGtch]

PR Description

Fixes #1387. Does so by ensuring that the basename used in glob is imediatly followed by a separator.

I considered two separators: ”_" and ”.”. Did I miss some separators @hoechenberger ?

Merge checklist

Maintainer, please confirm the following before merging.
If applicable:

• All comments are resolved
• This is not your own PR
• All CIs are happy
• PR title starts with [MRG]
• whats_new.rst is updated
• New contributors have been added to CITATION.cff
• PR description includes phrase "closes <#issue-number>"

[PierreGtch]

@hoechenberger ready for review :)

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 97.48%. Comparing base (4ac8005) to head (0120653).
Report is 1 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #1388   +/-   ##
=======================================
  Coverage   97.48%   97.48%           
=======================================
  Files          40       40           
  Lines        9014     9023    +9     
=======================================
+ Hits         8787     8796    +9     
  Misses        227      227           

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[hoechenberger]

LGTM! Excellent, @PierreGtch