refactor: simplify table feature parsing

[scovich]

What changes are proposed in this pull request?

There's a semantic gap in strum's EnumString: The parsing API it derives is always fallible (impl FromString and TryFrom, both with strum parsing error), but enums with a default variant have infallible parsing (because any unknown value goes into the default).

Define and use a new trait, IntoTableFeature, which mimicks Into. We can't "just" impl From for TableFeature because the blanket impl<T: From> TryFrom for T conflicts with the impl TryFrom for TableFeature strum emits.

Result: Code that works with table features no longer needs to parse+unwrap, and there's now a narrow waist to update some day if/when this gets fixed upstream (just remove the extension trait and impl From for TableFeature instead).

See also

• EnumString macro ignores parse_err_ty when there is a default variant Peternator7/strum#430
• Support infallible EnumString for enums with a default variant Peternator7/strum#432

How was this change tested?

Updated unit tests.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 85.88%. Comparing base (0c27272) to head (8e385c2).
⚠️ Report is 1 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1878      +/-   ##
==========================================
- Coverage   85.88%   85.88%   -0.01%     
==========================================
  Files         139      139              
  Lines       40065    40030      -35     
  Branches    40065    40030      -35     
==========================================
- Hits        34410    34379      -31     
+ Misses       4159     4158       -1     
+ Partials     1496     1493       -3     

☔ 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.

[scovich]

EnumIter + exhaustive match ensures that all present and future features are covered. Which also eliminates the need for two separate tests.

[scottsand-db]

nice!

[scottsand-db]

Neat fix! Thanks. LGTM

[DrakeLin]

looks great, thanks for the change