Update trees to 4.4.31 (com-lihaoyi#1602)

Pull request: com-lihaoyi#1602

build.sc

@@ -114,7 +114,7 @@ object Deps {
   val scalaCheck = ivy"org.scalacheck::scalacheck:1.15.4"
   def scalaCompiler(scalaVersion: String) = ivy"org.scala-lang:scala-compiler:${scalaVersion}"
   val scalafmtDynamic = ivy"org.scalameta::scalafmt-dynamic:3.0.8"
-  val scalametaTrees = ivy"org.scalameta::trees:4.4.30"
+  val scalametaTrees = ivy"org.scalameta::trees:4.4.31"
   def scalaReflect(scalaVersion: String) = ivy"org.scala-lang:scala-reflect:${scalaVersion}"
   def scalacScoveragePlugin = ivy"org.scoverage:::scalac-scoverage-plugin:1.4.10"
   val sourcecode = ivy"com.lihaoyi::sourcecode:0.2.7"
@@ -362,7 +362,6 @@ object main extends MillModule {
   }
 }
 
-
 object testrunner extends MillModule {
   override def moduleDeps = Seq(scalalib.api, main.util)
 }