Swap MappedLocalTime and LocalResult type alias

[pitdicker]

In #1501 I thought renaming LocalResult to MappedLocalTime would be entirely without consequences as long as there is a type alias with the old name. Turns out there is one case where a type alias behaves differently 😞. You can't import enum variants from a type alias with use chrono::LocalResult::*.

We have two choices:

• revert the rename entirely for the 0.4.x versions.
• change the enum definition to be on LocalResult, and use the type alias everywhere else.

The second choice has my preference. The docs look mostly sane, but break down once you come to the trait implementations section:

...

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 91.82%. Comparing base (ca3c3b6) to head (19dd217).

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #1547   +/-   ##
=======================================
  Coverage   91.82%   91.82%           
=======================================
  Files          40       40           
  Lines       18345    18345           
=======================================
  Hits        16846    16846           
  Misses       1499     1499           

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[djc]

Definitely annoying that importing the variants doesn't work correctly.

[pitdicker]

Published.

I'll look through the rust issue tracker if there is anything about type aliases for enums.

[pitdicker]

Opened rust-lang/rust#123131.