test support of shebang in script files

scalameta/scalameta#3812

Author: bjaglin

scalafix-tests/integration/src/test/scala/scalafix/tests/cli/CliSyntacticSuite.scala

@@ -312,6 +312,7 @@ class CliSyntacticSuite extends BaseCliSuite {
   check(
     name = "fix script files",
     originalLayout = s"""|/a.sc
+      |#!/usr/bin/env -S scala-cli shebang
       |def foo = { println(s"hello") }
       |lazy val bar = project
       |""".stripMargin,
@@ -321,6 +322,7 @@ class CliSyntacticSuite extends BaseCliSuite {
       "a.sc"
     ),
     expectedLayout = s"""|/a.sc
+      |#!/usr/bin/env -S scala-cli shebang
       |def foo = { println("hello") }
       |lazy val bar = project
       |""".stripMargin,