Empty stack trace since it does not help users.

src/main/scala/com/github/tanishiking/scalaunfmt/cli/Cli.scala

@@ -30,10 +30,12 @@ object Cli {
     } match {
       case Success(v) => v
       case Failure(e: NoSuchFileException) =>
-        throw new IllegalArgumentException(
+        val exception = new IllegalArgumentException(
           s"""Configuration file ${e.getFile} not found.
-             |Provide the file in reference to https://github.com/tanishiking/scalaunfmt#configuration""".stripMargin
+Provide the file in reference to https://github.com/tanishiking/scalaunfmt#configuration""".stripMargin
         )
+        exception.setStackTrace(Array.empty)
+        throw exception
       case Failure(e) => throw e // unknown
     }
 

src/test/scala/com/github/tanishiking/scalaunfmt/cli/CliSpec.scala

@@ -18,6 +18,7 @@ class CliSpec extends FunSpec with Matchers {
           Cli.run(opt, System.out, System.err)
         }
         assert(ex.getMessage.contains("Configuration file NO.SUCH.FILE.conf not found."))
+        assert(ex.getStackTrace.isEmpty)
       }
 
       it("should throw exception for unparsable config") {