Upgrade scalafmt + sbt-scalafmt + revert wrong 3.8.3 formatting

Author: mkurz

.scalafmt.conf

@@ -11,4 +11,4 @@ rewrite.sortModifiers.order = [ "private", "protected", "final", "sealed", "abst
 spaces.inImportCurlyBraces = true   # more idiomatic to include whitepsace in import x.{ yyy }
 trailingCommas = preserve
 newlines.afterCurlyLambda = preserve
-version = 3.8.3
+version = 3.8.4

project/plugins.sbt

@@ -1,5 +1,5 @@
 addSbtPlugin("com.eed3si9n"       % "sbt-assembly"    % "2.1.5")
-addSbtPlugin("org.scalameta"      % "sbt-scalafmt"    % "2.5.2")
+addSbtPlugin("org.scalameta"      % "sbt-scalafmt"    % "2.5.4")
 addSbtPlugin("com.typesafe"       % "sbt-mima-plugin" % "1.1.4")
 addSbtPlugin("de.heikoseeberger"  % "sbt-header"      % "5.10.0")
 addSbtPlugin("pl.project13.scala" % "sbt-jmh"         % "0.4.7")