New enum syntax: Short constructor syntax introduced for entries, optional commas between entries, semicolon after entries. #KT-7605 Fixed.

Grammar changed accordingly.
Semicolons prohibited after an entry except the last one.
Only one initializer is allowed per entry.
EnumReferenceExpression AST node introduced.
Some tests fixed, a pair of new tests written. Kotlin code inside project fixed.
Formatter and intendation tests fixed accordingly.
Stub version is incremented.

idea/testData/formatter/DelegationList.after.inv.kt

@@ -27,14 +27,9 @@ open class C1
 open class C2
 
 enum class Test : A1 {
-    FIRST_ITEM : Test(), C1(),
-            C2()
+    FIRST_ITEM : Test()
     SECOND_ITEM :
             Test()
-
-    THIRD_ITEM : Test(),
-            C1()
-    FORTH_ITEM : Test()
 }
 
 // SET_TRUE: ALIGN_MULTILINE_EXTENDS_LIST

idea/testData/formatter/DelegationList.after.kt

@@ -27,14 +27,9 @@ open class C1
 open class C2
 
 enum class Test : A1 {
-    FIRST_ITEM : Test(), C1(),
-                 C2()
+    FIRST_ITEM : Test()
     SECOND_ITEM :
             Test()
-
-    THIRD_ITEM : Test(),
-                 C1()
-    FORTH_ITEM : Test()
 }
 
 // SET_TRUE: ALIGN_MULTILINE_EXTENDS_LIST

idea/testData/formatter/DelegationList.kt

@@ -27,13 +27,9 @@ open class C1
 open class C2
 
 enum class Test : A1 {
-    FIRST_ITEM : Test(), C1(),
-    C2()
+    FIRST_ITEM : Test()
     SECOND_ITEM :
     Test()
-
-    THIRD_ITEM : Test(),
-    C1() FORTH_ITEM : Test()
 }
 
 // SET_TRUE: ALIGN_MULTILINE_EXTENDS_LIST