Fix attribute pickling

Author: nicolasstucki

compiler/src/dotty/tools/dotc/core/tasty/AttributePickler.scala

@@ -16,9 +16,10 @@ object AttributePickler:
   ): Unit =
     if attributes.scala2StandardLibrary || attributes.explicitNulls then // or any other attribute is set
       pickler.newSection(AttributesSection, buf)
-    // Pickle attributes
-    if attributes.scala2StandardLibrary then buf.writeNat(TastyFormat.SCALA2STANDARDLIBRARYattr)
-    if attributes.explicitNulls then buf.writeNat(TastyFormat.EXPLICITNULLSattr)
+      // Pickle attributes
+      if attributes.scala2StandardLibrary then buf.writeNat(TastyFormat.SCALA2STANDARDLIBRARYattr)
+      if attributes.explicitNulls then buf.writeNat(TastyFormat.EXPLICITNULLSattr)
+    end if
 
   end pickleAttributes