since pep8.py complains about blank lines after decorators, add rule to remove them

python/src/com/jetbrains/python/formatter/PythonFormattingModelBuilder.java

@@ -90,6 +90,9 @@ public class PythonFormattingModelBuilder implements FormattingModelBuilderEx, C
 
       .before(ARGUMENT_LIST).spaceIf(commonSettings.SPACE_BEFORE_METHOD_CALL_PARENTHESES)
 
+      .around(DECORATOR_CALL).spacing(1, Integer.MAX_VALUE, 0, true, 0)
+      .after(DECORATOR_LIST).spacing(1, Integer.MAX_VALUE, 0, true, 0)
+
       .aroundInside(EQ, ASSIGNMENT_STATEMENT).spaceIf(commonSettings.SPACE_AROUND_ASSIGNMENT_OPERATORS)
       .aroundInside(EQ, NAMED_PARAMETER).spaceIf(pySettings.SPACE_AROUND_EQ_IN_NAMED_PARAMETER)
       .aroundInside(EQ, KEYWORD_ARGUMENT_EXPRESSION).spaceIf(pySettings.SPACE_AROUND_EQ_IN_KEYWORD_ARGUMENT)

python/testData/formatter/blankLineAfterDecorator.py

@@ -0,0 +1,5 @@
+@foo
+
+@bar
+
+def baz(): pass

python/testData/formatter/blankLineAfterDecorator_after.py

@@ -0,0 +1,3 @@
+@foo
+@bar
+def baz(): pass

python/testSrc/com/jetbrains/python/PyFormatterTest.java

@@ -179,6 +179,10 @@ public class PyFormatterTest extends PyTestCase {
     doTest();
   }
 
+  public void testBlankLineAfterDecorator() {
+    doTest();
+  }
+
   public void testPsiFormatting() { // IDEA-69724
     String initial =
       "def method_name(\n" +