Use inspect.getdoc to get model description

[tiangolo]

Change Summary

Use inspect.getdoc to get model description instead of the custom function clean_docstring.

It also allows models to inherit a description, the same way classes inherit a docstring.

Ref: https://docs.python.org/3/library/inspect.html#inspect.getdoc

Related issue number

Minor change without issue.

Checklist

• Unit tests for the changes exist
• Tests pass on CI and coverage remains at 100%
• Documentation reflects the changes where applicable
• HISTORY.rst has been updated
  • if this is the first change since a release, please add a new section
  • include the issue number or this pull request number #<number>
  • include your github username @<whomever>

[tiangolo]

Let me know if you want to have extra tests for models inheriting the description.

[codecov]

Codecov Report

Merging #657 into master will not change coverage.
The diff coverage is 100%.

@@          Coverage Diff          @@
##           master   #657   +/-   ##
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  Coverage     100%   100%           
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  Files          15     15           
  Lines        2673   2672    -1     
  Branches      530    530           
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- Hits         2673   2672    -1

[samuelcolvin]

LGTM, just conflicts and rebase/update history.

[tiangolo]

Sorry for the delay on this.

Thanks for moving it forward and merging.