Add T::Enum handler

[dduugg]

Resolves #43

Adds a simple T::Enum handler, which registers each enum as a constant. I don't love the formatting, but the content is clear enough:

The collapsed view is decent though:

[codecov]

Codecov Report

Merging #44 (3e6fa76) into master (0e0dfd3) will not change coverage.
The diff coverage is 100.00%.

@@            Coverage Diff            @@
##            master       #44   +/-   ##
=========================================
  Coverage   100.00%   100.00%           
=========================================
  Files            2         3    +1     
  Lines          266       287   +21     
=========================================
+ Hits           266       287   +21     

Impacted Files	Coverage Δ
spec/yard_sorbet/enums_handler_spec.rb	100.00% <100.00%> (ø)

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[KaanOzkan]

This will display local variable assignments inside enums block as a constant in the yard output but I guess that's wrong usage of enums block and therefore we are okay with it?

[dduugg]

@KaanOzkan great catch! I think i fixed it in the latest commit, check it out. (I also checked non-enum constant assignments, e.g. Foo = 1, in an enums block, and sorbet raises a RuntimeError, so we don't have to contemplate that.)

[dduugg]

This will appear as new(diamonds_serialized_value) in the documentation, with no other reference to diamonds_serialized_value for clarity. I don't love that, but I can live with it. LMK if you have any thoughts.

[KaanOzkan]

I'm okay with it either way, I don't think this case is that important since people shouldn't be adding extra logic such as local variable assignments to enums blocks.

[dduugg]

This turns out to be consistent with YARD, if you write something pathological like:

class A
  b = 1
  C = b
end

so I think this is 🆗