Replace deprecated "_phase" suffix in reproin heuristic with "part-phase" entity

[tsalo]

Closes #769. This is working on DICOMs associated with https://openneuro.org/datasets/ds005250.

Changes proposed:

• Track previous and next sequence info in ReproIn's infotodict.
• Rename s variable to curr_seqinfo for improved clarity. Moved to Rename s variable to curr_seqinfo in reproin heuristic #779.
• For non-SBRef, non-fieldmap scans, set "part" entity to "phase" for phase data instead of setting the suffix to "phase".
• For magnitude non-SBRef, non-fieldmap scans, check if the next sequence has the same series_description and is a phase scan. If it is, set "part" to "mag".

[codecov]

Codecov Report

Attention: Patch coverage is 90.90909% with 2 lines in your changes missing coverage. Please review.

Project coverage is 82.15%. Comparing base (a0a3635) to head (59bb2ec).

Files	Patch %	Lines
heudiconv/heuristics/reproin.py	90.90%	2 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master     #770      +/-   ##
==========================================
+ Coverage   82.08%   82.15%   +0.06%     
==========================================
  Files          42       42              
  Lines        4215     4230      +15     
==========================================
+ Hits         3460     3475      +15     
  Misses        755      755              

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[yarikoptic]

Rename s variable to curr_seqinfo for improved clarity.

yeah, but complicates review a little due to diff now including changes I can ignore or not and need to decide when looking...

Could you submit a separate PR with that typo fix and such a rename (so no functionality change) and then let's improve this one -- yet to grasp on all the changes, and as we do not have any nice testing for reproin heuristic, I wonder how we could add one :-/ I would really be shy to accept without some way to test. Locally I could do using smth like https://github.com/nipy/heudiconv/blob/master/utils/test-compare-two-versions.sh but could we do better?!

[tsalo]

👍 I've opened #779 with the variable name change.