add newline at the end of 'messages.scala'

Author: arainko

compiler/src/dotty/tools/dotc/reporting/messages.scala

@@ -2922,4 +2922,5 @@ class ToplevelDefCantBeInfix(sym: Symbol)(using Context)
       if sym.flags.is(Method) then "def"
       else if sym.flags.is(Mutable) then "var"
       else if sym.flags.is(Given) then "given"
-      else "val"
+      else "val"
+