scala: supporting mill files - minor CR changes

Author: azdrojowa123

scala/scala-api/src/icons/Icons.java

@@ -17,6 +17,7 @@ public interface Icons {
     Icon COMPILATION_CHARTS = getIcon("/org/jetbrains/plugins/scala/images/compilationCharts.svg", Icons.class);
 
     Icon SCALA_FILE = getIcon("/org/jetbrains/plugins/scala/images/fileScala.svg", Icons.class);
+    Icon MILL_FILE = getIcon("/org/jetbrains/plugins/scala/images/millFile.svg", Icons.class);
 
     Icon ADD_CLAUSE = getIcon("/org/jetbrains/plugins/scala/images/addClause.svg", Icons.class);
     Icon REMOVE_CLAUSE = getIcon("/org/jetbrains/plugins/scala/images/removeClause.svg", Icons.class);
@@ -77,7 +78,4 @@ public interface Icons {
 
     // X-Ray mode widget
     Icon PIN = getIcon("/org/jetbrains/plugins/scala/images/pin.svg", Icons.class);
-
-    // Mill file
-    Icon MILL_FILE = getIcon("/org/jetbrains/plugins/scala/images/millFile.svg", Icons.class);
 }

scala/scala-impl/resources/messages/ScalaBundle.properties

@@ -22,9 +22,6 @@ copy.scala.type=Copy Scala Type
 ### org/jetbrains/plugins/scala/actions/EditPackagePrefixAction.scala
 edit.package.prefix=Edit Package Prefix...
 
-### org/jetbrains/plugins/scala/projectView/FileNode/ScalaFileNode
-scala.file.mill.extension=mill
-
 ### org/jetbrains/plugins/scala/actions/MakeExplicitAction.scala
 make.implicit.conversion.explicit.action.text=Make implicit conversion explicit
 make.implicit.conversion.explicit.action.description=Make implicit conversion explicit

scala/scala-impl/src/org/jetbrains/plugins/scala/projectView/package.scala

@@ -34,13 +34,9 @@ package object projectView {
     }
 
     private def isMillFile(file: ScalaFile):Boolean = {
-      val psiFile = file.getContainingFile
-      if (psiFile == null) return false
-      val vf = psiFile.getVirtualFile
+      val vf = file.getVirtualFile
       if (vf == null) return false
-      val fileExt = FileUtilRt.getExtension(vf.getPath)
-      val millExt = ScalaBundle.message("scala.file.mill.extension")
-      fileExt == millExt
+      FileUtilRt.extensionEquals(vf.getPath, "mill")
     }
   }