PY-10972 Properly align elements of expressions without closing bracket on enter

instead of using artificially built indentation. It also covers all
collection literals, comprehensions and glued string literals in
parentheses most of which were overlooked in the previous implementation.

python/testSrc/com/jetbrains/python/PyEditingTest.java

@@ -365,7 +365,8 @@ public class PyEditingTest extends PyTestCase {
   public void testEndOfStringInParenth() {
     doTestEnter("print (\"foo\"<caret>\n" +
                 "    \"bar\")",
-                "print (\"foo\"\n\n" +
+                "print (\"foo\"\n" +
+                "       \n" +
                 "    \"bar\")");
   }
 
@@ -596,4 +597,49 @@ public class PyEditingTest extends PyTestCase {
   public void testIncompleteFunctionTypeComment() {
     doTypingTest('.');
   }
+
+  // PY-10972
+  public void testEnterInIncompleteTupleLiteral() {
+    doTypingTest("\n'baz'");
+  }
+
+  // PY-10972
+  public void testEnterInIncompleteListLiteral() {
+    doTypingTest("\n'baz'");
+  }
+
+  // PY-10972
+  public void testEnterInIncompleteSetLiteral() {
+    doTypingTest("\n'baz'");
+  }
+
+  // PY-10972
+  public void testEnterInIncompleteDictLiteral() {
+    doTypingTest("\n'baz'");
+  }
+
+  // PY-10972
+  public void testEnterInIncompleteGluedStringLiteralInParentheses() {
+    doTypingTest("\n'bar'");
+  }
+
+  // PY-10972
+  public void testEnterInIncompleteListComprehension() {
+    doTypingTest("\nfoo");
+  }
+
+  // PY-10972
+  public void testEnterInIncompleteSetComprehension() {
+    doTypingTest("\nfoo");
+  }
+
+  // PY-10972
+  public void testEnterInIncompleteDictComprehension() {
+    doTypingTest("\nfoo");
+  }
+
+  // PY-10972
+  public void testEnterInIncompleteParenthesizedGenerator() {
+    doTypingTest("\nfoo");
+  }
 }