Use encoded names in derivation macros

[BenFradet]

Here's how I tested it:

sealed trait Foo
case class Bar(xs: List[String]) extends Foo
case class Qux(i: Int, d: Option[Double]) extends Foo

val foo: Foo = Bar(List("abc", "def", "ghi"))
val json = foo.asJson.noSpaces
println(json)

[codecov-io]

Codecov Report

Merging #828 into master will decrease coverage by 0.08%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master     #828      +/-   ##
==========================================
- Coverage   86.91%   86.83%   -0.09%     
==========================================
  Files          71       71              
  Lines        2324     2324              
  Branches      175      186      +11     
==========================================
- Hits         2020     2018       -2     
- Misses        304      306       +2

Impacted Files	Coverage Δ
...o/circe/generic/util/macros/DerivationMacros.scala	76.47% <ø> (ø)	⬆️
...re/shared/src/main/scala/io/circe/KeyDecoder.scala	97.29% <0%> (-2.71%)	⬇️
.../core/shared/src/main/scala/io/circe/Decoder.scala	90.55% <0%> (-0.33%)	⬇️

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[travisbrown]

It'd be nice to have a failing test, but we can do that in a follow-up PR. Thanks, @BenFradet!

[BenFradet]

I can add it in this PR, no worries 👍

[travisbrown]

Great, thanks @BenFradet! I'll publish 0.9.1 as soon as it's ready and merged.

[BenFradet]

@travisbrown added an hygiene test for scala js, is this what you had in mind?

[travisbrown]

Yep, looks good to me (I just confirmed that cherry-picking the test commit onto master fails).

[BenFradet]

Cool stuff, looking forward to 0.9.1 👍