Single indent for multi-declarations for official codestyle (KT-27847)

#KT-27847 Fixed

idea/formatter/src/org/jetbrains/kotlin/idea/formatter/KotlinCommonBlock.kt

@@ -710,6 +710,13 @@ private val INDENT_RULES = arrayOf(
         }
         .continuationIf(KotlinCodeStyleSettings::CONTINUATION_INDENT_FOR_EXPRESSION_BODIES),
 
+    strategy("Destructuring declaration")
+        .within(KtNodeTypes.DESTRUCTURING_DECLARATION)
+        .forElement {
+            it.psi is KtExpression
+        }
+        .continuationIf(KotlinCodeStyleSettings::CONTINUATION_INDENT_FOR_EXPRESSION_BODIES),
+
     strategy("Indent for parts")
         .within(KtNodeTypes.PROPERTY, KtNodeTypes.FUN, KtNodeTypes.DESTRUCTURING_DECLARATION, KtNodeTypes.SECONDARY_CONSTRUCTOR)
         .notForType(

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

@@ -1,4 +1,11 @@
 fun foo() =
     2
 
+data class A(val a: Int, val b: Int)
+
+fun test() {
+    val (a, b) =
+        A()
+}
+
 // SET_TRUE: CONTINUATION_INDENT_FOR_EXPRESSION_BODIES

idea/testData/formatter/ContinuationIndentForExpressionBodies.kt

@@ -1,4 +1,11 @@
 fun foo() =
         2
 
+data class A(val a: Int, val b: Int)
+
+fun test() {
+    val (a, b) =
+            A()
+}
+
 // SET_TRUE: CONTINUATION_INDENT_FOR_EXPRESSION_BODIES