Document base_types.py

[SamWilsn]

This PR removes some unnecessary constants, renames some classes for consistency, and updates base_types.py to markdown.

Cute Animal Picture

[codecov-commenter]

Codecov Report

Attention: Patch coverage is 87.09677% with 8 lines in your changes missing coverage. Please review.

Project coverage is 74.12%. Comparing base (4d95303) to head (6fe5c0a).
Report is 391 commits behind head on master.

Files with missing lines	Patch %	Lines
...c/ethereum/arrow_glacier/vm/instructions/memory.py	0.00%	2 Missing ⚠️
src/ethereum/dao_fork/vm/instructions/memory.py	0.00%	2 Missing ⚠️
...rc/ethereum/gray_glacier/vm/instructions/memory.py	0.00%	2 Missing ⚠️
...rc/ethereum/muir_glacier/vm/instructions/memory.py	0.00%	2 Missing ⚠️

Additional details and impacted files

@@           Coverage Diff           @@
##           master     #883   +/-   ##
=======================================
  Coverage   74.12%   74.12%           
=======================================
  Files         572      572           
  Lines       32419    32423    +4     
=======================================
+ Hits        24030    24034    +4     
  Misses       8389     8389           

Flag	Coverage Δ
unittests	74.12% <87.09%> (+<0.01%)	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.