Enable rainbow highlighting for destructuring declaration entries

#KT-17652 Fixed

idea/src/org/jetbrains/kotlin/idea/highlighter/KotlinRainbowVisitor.kt

@@ -93,8 +93,10 @@ class KotlinRainbowVisitor : RainbowVisitor() {
         addInfo(getInfo(context, rainbowElement, rainbowElement.text, attributesKeyToUse))
     }
 
-    private fun PsiElement?.isRainbowDeclaration() =
+    private fun PsiElement?.isRainbowDeclaration(): Boolean =
-            (this is KtProperty && isLocal) || (this is KtParameter && getStrictParentOfType<KtPrimaryConstructor>() == null)
+            (this is KtProperty && isLocal) ||
+            (this is KtParameter && getStrictParentOfType<KtPrimaryConstructor>() == null) ||
+            this is KtDestructuringDeclarationEntry
 }
 
 private fun PsiElement.isAnonymousFunction(): Boolean = this is KtNamedFunction && nameIdentifier == null

idea/tests/org/jetbrains/kotlin/idea/highlighter/KotlinRainbowHighlighterTest.kt

@@ -70,7 +70,17 @@ class KotlinRainbowHighlighterTest : KotlinLightCodeInsightFixtureTestCase() {
                   System.out.println(<rainbow color='ff000004'>foo</rainbow>)
              }
         """)
+    }
 
+    fun testDestructuring() {
+        checkRainbow("""
+            fun foo() {
+                val (<rainbow color='ff000003'>a</rainbow>, <rainbow color='ff000004'>b</rainbow>) = 1 to 2
+
+                println(<rainbow color='ff000003'>a</rainbow>)
+                println(<rainbow color='ff000004'>b</rainbow>)
+            }
+        """)
     }
 
     private fun checkRainbow(code: String) {