Support formatting of 'where' clauses

#KT-14083 Fixed

idea/testData/formatter/WhereClause.after.kt

@@ -0,0 +1,12 @@
+abstract class RustNavigationContributorBase<T> protected constructor(
+        private val indexKey: StubIndexKey<String, T>,
+        private val clazz: Class<T>
+) : ChooseByNameContributor, GotoClassContributor
+        where T : NavigationItem,
+              T : RustNamedElement {
+}
+
+fun <T> foo()
+        where T : NavigationItem,
+              T : RustNamedElement {
+}

idea/testData/formatter/WhereClause.kt

@@ -0,0 +1,12 @@
+abstract class RustNavigationContributorBase<T> protected constructor(
+        private val indexKey: StubIndexKey<String, T>,
+        private val clazz: Class<T>
+) : ChooseByNameContributor, GotoClassContributor
+where T : NavigationItem,
+T : RustNamedElement {
+}
+
+fun <T> foo()
+where T : NavigationItem,
+T : RustNamedElement {
+}