doc: Update API documentation

[crandmck]

Review doc comments for Reader.

Changes in this pull request

Edits to doc comments in Rust code for clarity and completeness.

TO DO:

• Change all references to errors to be to the [Error] enum

Checklist

• This PR represents a single feature, fix, or change.
• All applicable changes have been documented.
• Any TO DO items (or similar) have been entered as GitHub issues and the link to that issue has been included in a comment.

[codecov]

Codecov Report

Attention: Patch coverage is 0% with 2 lines in your changes missing coverage. Please review.

Project coverage is 24.25%. Comparing base (5325170) to head (b3f0868).
Report is 1 commits behind head on main.

Files with missing lines	Patch %	Lines
sdk/src/ingredient.rs	0.00%	2 Missing ⚠️

Additional details and impacted files

@@           Coverage Diff           @@
##             main     #621   +/-   ##
=======================================
  Coverage   24.25%   24.25%           
=======================================
  Files          88       88           
  Lines       22100    22100           
=======================================
  Hits         5360     5360           
  Misses      16740    16740           

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[gpeacock]

I requested some changes but otherwise good to go.

[crandmck]

Addressed your comments.