Fixed Pseduo Param for Region in Layers sections

[nicklit]

Issue #, if available:

Description of changes:

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.

[codecov-io]

Codecov Report

Merging #796 into master will decrease coverage by 0.53%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master     #796      +/-   ##
==========================================
- Coverage   94.85%   94.32%   -0.54%     
==========================================
  Files          67       67              
  Lines        3772     2626    -1146     
  Branches      828      464     -364     
==========================================
- Hits         3578     2477    -1101     
+ Misses         97       78      -19     
+ Partials       97       71      -26

Impacted Files	Coverage Δ
samtranslator/yaml_helper.py	80% <0%> (-8.89%)	⬇️
samtranslator/model/s3_utils/uri_parser.py	71.42% <0%> (-6.35%)	⬇️
samtranslator/model/eventsources/push.py	86.59% <0%> (-3.01%)	⬇️
samtranslator/model/eventsources/pull.py	91.48% <0%> (-2.8%)	⬇️
...el/preferences/deployment_preference_collection.py	88.88% <0%> (-2.78%)	⬇️
samtranslator/translator/arn_generator.py	86.95% <0%> (-1.94%)	⬇️
samtranslator/model/intrinsics.py	95% <0%> (-1.78%)	⬇️
samtranslator/swagger/swagger.py	97.84% <0%> (-0.74%)	⬇️
samtranslator/model/api/api_generator.py	95.9% <0%> (-0.66%)	⬇️
samtranslator/translator/logical_id_generator.py	90% <0%> (-0.48%)	⬇️
... and 25 more

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[jlhood]

Thanks for fixing this!