Support incremental analysis of comment and kdoc

#KT-35189 Fixed

idea/testData/codeInsight/outOfBlock/Comment.kt

@@ -0,0 +1,7 @@
+// OUT_OF_CODE_BLOCK: FALSE
+// TYPE: '//'
+// ERROR: A 'return' expression required in a function with a block body ('{...}')
+
+fun comment(): String {
+    <caret>return ""
+}