Use django builtin for determining through field name

[mjsir911]

Description

Related Issue

Fixes #1126

Motivation and Context

How Has This Been Tested?

Screenshots (if appropriate):

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)

Checklist:

• I have run the pre-commit run command to format and lint.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I have read the CONTRIBUTING document.
• I have added tests to cover my changes.
• I have added my name and/or github handle to AUTHORS.rst
• I have added my change to CHANGES.rst
• All new and existing tests passed.

[codecov]

Codecov Report

Merging #1218 (92c5f05) into master (4b22c58) will not change coverage.
The diff coverage is 100.00%.

@@           Coverage Diff           @@
##           master    #1218   +/-   ##
=======================================
  Coverage   97.08%   97.08%           
=======================================
  Files          23       23           
  Lines        1271     1271           
  Branches      208      208           
=======================================
  Hits         1234     1234           
  Misses         19       19           
  Partials       18       18           

Files Changed	Coverage Δ
simple_history/models.py	96.71% <100.00%> (ø)

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[ddabble]

Very nice! See below for a few small change requests.

Also, please resolve the merge conflicts in CHANGES.rst 😊

[ddabble]

Looks good, thank you! 😊