docs(dynamodb): fix typos

[kdnakt]

Issue # (if applicable)

N/A

Reason for this change

Fixed typos in README and code comments.

Checklist

• My code adheres to the CONTRIBUTING GUIDE and DESIGN GUIDELINES

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

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 81.38%. Comparing base (bbdd42c) to head (ae72bb7).
Report is 24 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main   #32852      +/-   ##
==========================================
- Coverage   81.52%   81.38%   -0.15%     
==========================================
  Files         222      222              
  Lines       13715    13695      -20     
  Branches     2417     2412       -5     
==========================================
- Hits        11181    11145      -36     
- Misses       2254     2271      +17     
+ Partials      280      279       -1     

Flag	Coverage Δ
suite.unit	81.38% <ø> (-0.15%)	⬇️

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

Components	Coverage Δ
packages/aws-cdk	80.69% <ø> (-0.29%)	⬇️
packages/aws-cdk-lib/core	82.09% <ø> (ø)

[aws-cdk-automation]

AWS CodeBuild CI Report

• CodeBuild project: AutoBuildv2Project1C6BFA3F-wQm2hXv2jqQv
• Commit ID: ae72bb7
• Result: FAILED
• Build Logs (available for 30 days)

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