refactor(rust): Add FromIterator impls for PlSmallStr

[nameexhaustion]

From PlSmallStr, &PlSmallStr, and all the iterator types that String::from_iter supports

[codecov]

Codecov Report

Attention: Patch coverage is 8.33333% with 33 lines in your changes missing coverage. Please review.

Project coverage is 79.84%. Comparing base (ab25b3e) to head (d1832fe).
Report is 2 commits behind head on main.

Files with missing lines	Patch %	Lines
crates/polars-utils/src/pl_str.rs	8.33%	33 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main   #18509      +/-   ##
==========================================
- Coverage   79.85%   79.84%   -0.01%     
==========================================
  Files        1501     1501              
  Lines      201829   201865      +36     
  Branches     2868     2868              
==========================================
+ Hits       161174   161189      +15     
- Misses      40109    40130      +21     
  Partials      546      546              

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[ritchie46]

I am wondering if we should. As a collect now "seems" to work, but it goes via a String allocation, which might not be that clear to the callee.

[nameexhaustion]

I am wondering if we should. As a collect now "seems" to work, but it goes via a String allocation, which might not be that clear to the callee.

I don't have any preference - though I suppose it would let us swap it out for more performant impls in the future?

@orlp might have some ideas - this was originally requested by him

[orlp]

I mean it should be easy enough to swap the impl once we use compact_str (my suggestion for the backing crate for now).

[nameexhaustion]

I mean it should be easy enough to swap the impl once we use compact_str (my suggestion for the backing crate for now).

Ah, yes - we indeed now have native From impls provided by compact_str - have pushed a commit to update

[nameexhaustion]

drive-by - add From<Inner>