Address boundary handling issues in non-blocking raw text reader, and its blocking wrapper

[nirosys]

Issue #, if available: n/a

Description of changes:
Previous implementation of the non-blocking reader, and its blocking wrapper, had two bugs when handling incomplete errors, and continuing after an incomplete error.

The non-blocking reader did not take into account the step_out nesting when unsetting the need_continue. When stepping out of a container that contained a container that had not yet been read, this would result in the reader stepping out beyond the target depth.

The blocking reader did not properly mark the stream as complete when stepping out of a container. If a step_out caused the last remaining data from the stream to be read (completing the stream) root level values at the end of the stream could be ambiguous and continue to cause incomplete data errors, until the stream had been marked complete.

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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.

[zslayton]

This diff looks good, could you add 1+ unit tests showing it's fixed?

[nirosys]

Absolutely, porting them over from my other branch now.

[codecov]

Codecov Report

Patch coverage: 97.91% and project coverage change: +0.04 🎉

Comparison is base (cffa745) 89.47% compared to head (f8b43e2) 89.52%.

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #488      +/-   ##
==========================================
+ Coverage   89.47%   89.52%   +0.04%     
==========================================
  Files          76       76              
  Lines       13704    13747      +43     
==========================================
+ Hits        12262    12307      +45     
+ Misses       1442     1440       -2     

Impacted Files	Coverage Δ
src/text/raw_text_reader.rs	97.85% <97.87%> (-0.02%)	⬇️
src/text/non_blocking/raw_text_reader.rs	89.51% <100.00%> (+0.34%)	⬆️

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[nirosys]

Added a unit test which currently validates the step_out nesting fix when continuing from an incomplete. I do not think it validates the end of stream on step_out anymore (It has been modified since I found the issue). It will take me a bit to repro, in order to get the data, and read sizes, to line up so it exhausts on step_out.

I'll make sure to include that in the format agnostic PR if no one minds its absence here.

[zslayton]

Nice! Can you address the clippy warnings before merging?

[nirosys]

tyvm! Added commit for clippy issues.