Improve AMBIGUOUS_CALLS renderer

idea/testData/diagnosticMessage/overloadResolutionAmbiguityTxt.kt

@@ -0,0 +1,21 @@
+// !DIAGNOSTICS_NUMBER: 1
+// !DIAGNOSTICS: OVERLOAD_RESOLUTION_AMBIGUITY
+// !MESSAGE_TYPE: TEXT
+
+package a.b
+
+val ref1 =  ::foo
+
+fun <T> foo(a: kotlin.String, t: T) {
+
+}
+
+fun <T> foo(b: String, t : T) {
+
+}
+
+fun foo(i: Int) {
+
+}
+
+class String