PY-18486 Don't auto close quotes that start docstring, so PythonEnterHandler could complete it

python/testData/editing/tripleQuotesThenEnterInsertsDocstring.after.py

@@ -0,0 +1,7 @@
+def f(x):
+    """
+    
+    :param x: 
+    :return: 
+    """
+    return 42

python/testData/editing/tripleQuotesThenEnterInsertsDocstring.py

@@ -0,0 +1,3 @@
+def f(x):
+    <caret>
+    return 42