Code completion: changed dummy identifier for basic completion to ignore context ahead + no invisible symbols on first completion even if nothing matches

idea/testData/completion/basic/common/namedParameters/NotOnlyNamedParameters2.kt

@@ -0,0 +1,9 @@
+fun foo(first: Int, second: Int, third: String) {
+}
+
+fun test(p: Int) = foo(<caret>second = 3)
+
+// EXIST: p
+// EXIST: first
+// EXIST: second
+// EXIST: third