Formatter: fix line break between declarations with annotations

#KT-35093 Fixed
#KT-35106 Fixed

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

@@ -105,8 +105,7 @@ class KotlinSpacingBuilder(val commonCodeStyleSettings: CommonCodeStyleSettings,
                 val leftEndsWithComment = lastChild is PsiComment && lastChild.tokenType == KtTokens.EOL_COMMENT
                 val dependentSpacingRule = DependentSpacingRule(Trigger.HAS_LINE_FEEDS).registerData(Anchor.MIN_LINE_FEEDS, emptyLines + 1)
                 val textRange = left.node
-                    ?.children()
-                    ?.firstOrNull { it.elementType !in KtTokens.WHITE_SPACE_OR_COMMENT_BIT_SET }
+                    ?.startOfDeclaration()
                     ?.startOffset
                     ?.let { TextRange.create(it, left.textRange.endOffset) }
                     ?: left.textRange

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

@@ -95,9 +95,9 @@ fun createSpacingBuilder(settings: CodeStyleSettings, builderUtil: KotlinSpacing
                 _: ASTBlock,
                 right: ASTBlock
             ): Spacing? {
-                val firstChild = right.node?.firstChildNode as? PsiComment ?: return null
-                val whiteSpace = firstChild.nextSibling as? PsiWhiteSpace ?: return null
-                return if (StringUtil.containsLineBreak(firstChild.text) || StringUtil.containsLineBreak(whiteSpace.text)) {
+                val node = right.node ?: return null
+                val elementStart = node.startOfDeclaration() ?: return null
+                return if (StringUtil.containsLineBreak(node.text.subSequence(0, elementStart.startOffset - node.startOffset).trimStart())) {
                     createSpacing(0, minLineFeeds = 2)
                 } else
                     null

idea/testData/formatter/EmptyLineBetweeAbstractFunctions.after.kt

@@ -13,6 +13,10 @@ interface Some {
      */
     fun f6()
     fun f7()
+
+    @NotNull
+    fun f8()
+    fun f9()
 }
 
 abstract class Abstract() {

idea/testData/formatter/EmptyLineBetweeAbstractFunctions.kt

@@ -11,6 +11,9 @@ interface Some {
      */
     fun f6()
     fun f7()
+    @NotNull
+    fun f8()
+    fun f9()
 }
 
 abstract class Abstract() {

idea/testData/multiModuleQuickFix/createExpect/withAnnotations/header/My.kt.after

@@ -4,6 +4,7 @@
 annotation class CommonAnnotation
 expect class My {
     tailrec fun foo(arg: Int): Int
+
     @CommonAnnotation
     fun initialize()