Extract Function: Allow to select fragments which start with comment

idea/testData/refactoring/extractFunction/basic/fragmentWithComment.kt.after

@@ -0,0 +1,12 @@
+// NEXT_SIBLING:
+fun b(a: Int): Boolean {
+    // test
+    println(a)
+    if (a > 0) return true
+    return false
+}
+
+fun foo(a: Int): Int {
+    if (b(a)) return a
+    return -a
+}