Resource Bundles: Implement references on Kotlin string literals

#KT-6946 In Progress

compiler/frontend/src/org/jetbrains/kotlin/psi/psiUtil/jetPsiUtil.kt

@@ -405,3 +405,5 @@ public fun JetDeclaration.visibilityModifier(): PsiElement? {
 
 public fun JetDeclaration.visibilityModifierType(): JetModifierKeywordToken?
         = visibilityModifier()?.node?.elementType as JetModifierKeywordToken?
+
+public fun JetStringTemplateExpression.isPlain() = entries.all { it is JetLiteralStringTemplateEntry }

compiler/tests/org/jetbrains/kotlin/test/InTextDirectivesUtils.java

@@ -158,7 +158,7 @@ public final class InTextDirectivesUtils {
         List<String> resultPrefixes = Lists.newArrayList();
 
         for (String prefix : prefixes) {
-            if (prefix.startsWith("//")) {
+            if (prefix.startsWith("//") || prefix.startsWith("##")) {
                 resultPrefixes.add(StringUtil.trimLeading(prefix.substring(2)));
             }
             else {
@@ -181,7 +181,7 @@ public final class InTextDirectivesUtils {
 
                 while ((line = reader.readLine()) != null) {
                     line = line.trim();
-                    if (line.startsWith("//")) {
+                    if (line.startsWith("//") || line.startsWith("##")) {
                         String uncommentedLine = line.substring(2).trim();
                         if (!uncommentedLine.isEmpty()) {
                             result.add(uncommentedLine);