Fix scalacOptions fatal warnings breaking publishLocal & publish

Prior to this PR, the recently added scalacOption -Xfatal-warnings would
cause publishLocal to fail.  The underlying defect is the fact that
ScalaNative plugin 0.4.0-M2, and probably other versions, emits a
debugging warning for the an empty mixin phase. This warning was supposed
to be bootstrapping which would disappear.

The current workaround is logically correct and has a vanishingly small
cost.

Tested manually by starting from clean code and .ivy2 directories
and running publishLocal.  No errors seen.

This PR just restores normal operation, no documentation impact. The
build.sbt code is the documentation (inside joke).

Author: LeeTibbert

build.sbt

@@ -38,56 +38,66 @@ lazy val commonSettings = Seq(
     "-Ywarn-unused-import",
     "-Xfatal-warnings"
   ),
+  Compile / doc / scalacOptions -= "-Xfatal-warnings",
   publish / skip := true,
   publishLocal / skip := true
 )
 
-lazy val core = project.in(file("core"))
+lazy val core = project
+  .in(file("core"))
   .settings(name := "native-loop-core")
   .settings(commonSettings)
   .settings(publish / skip := false)
   .settings(publishLocal / skip := false)
   .enablePlugins(ScalaNativePlugin)
 
-lazy val pipe = project.in(file("pipe"))
+lazy val pipe = project
+  .in(file("pipe"))
   .settings(commonSettings)
   .enablePlugins(ScalaNativePlugin)
   .dependsOn(core)
 
-lazy val client = project.in(file("client"))
+lazy val client = project
+  .in(file("client"))
   .settings(commonSettings)
   .enablePlugins(ScalaNativePlugin)
   .dependsOn(core)
 
-lazy val server = project.in(file("server"))
+lazy val server = project
+  .in(file("server"))
   .settings(commonSettings)
   .enablePlugins(ScalaNativePlugin)
   .dependsOn(core)
 
-lazy val scalaJsCompat = project.in(file("scalajs-compat"))
+lazy val scalaJsCompat = project
+  .in(file("scalajs-compat"))
   .settings(name := "native-loop-js-compat")
   .settings(commonSettings)
   .settings(publish / skip := false)
   .settings(publishLocal / skip := false)
   .enablePlugins(ScalaNativePlugin)
   .dependsOn(core)
 
-lazy val serverExample = project.in(file("examples/server"))
+lazy val serverExample = project
+  .in(file("examples/server"))
   .settings(commonSettings)
   .enablePlugins(ScalaNativePlugin)
   .dependsOn(core, server, client)
 
-lazy val pipeExample = project.in(file("examples/pipe"))
+lazy val pipeExample = project
+  .in(file("examples/pipe"))
   .settings(commonSettings)
   .enablePlugins(ScalaNativePlugin)
   .dependsOn(core, pipe, client)
 
-lazy val curlExample = project.in(file("examples/curl"))
+lazy val curlExample = project
+  .in(file("examples/curl"))
   .settings(commonSettings)
   .enablePlugins(ScalaNativePlugin)
   .dependsOn(core, client)
 
-lazy val timerExample = project.in(file("examples/timer"))
+lazy val timerExample = project
+  .in(file("examples/timer"))
   .settings(commonSettings)
   .enablePlugins(ScalaNativePlugin)
   .dependsOn(core)