Code Insight: Support file path references inside of Kotlin string literals

#KT-11704 Fixed

idea/idea-completion/testData/basic/multifile/FileRefInStringLiteral/FileRefInStringLiteral.kt

@@ -0,0 +1,6 @@
+// NUMBER: 1
+// EXIST: foo.txt
+
+fun foo() {
+    val s = "fo<caret>"
+}

idea/idea-completion/testData/basic/multifile/FileRefInStringLiteralNoPrefix/FileRefInStringLiteralNoPrefix.kt

@@ -0,0 +1,8 @@
+// NUMBER: 3
+// EXIST: foo.txt
+// EXIST: bar.txt
+// EXIST: FileRefInStringLiteralNoPrefix.kt
+
+fun foo() {
+    val s = "<caret>"
+}

idea/idea-completion/testData/handlers/multifile/FileRefInStringLiteralEnter-1.kt

@@ -0,0 +1,3 @@
+fun foo() {
+    val s = "fo<caret>something"
+}

idea/idea-completion/testData/handlers/multifile/FileRefInStringLiteralEnter-2.kt

@@ -0,0 +1 @@
+// Empty file to satisfy test framework requirements

idea/idea-completion/testData/handlers/multifile/FileRefInStringLiteralEnter.kt.after

@@ -0,0 +1,3 @@
+fun foo() {
+    val s = "foo.txt"
+}

idea/idea-completion/testData/handlers/multifile/FileRefInStringLiteralTab-1.kt

@@ -0,0 +1,3 @@
+fun foo() {
+    val s = "fo<caret>something"
+}

idea/idea-completion/testData/handlers/multifile/FileRefInStringLiteralTab-2.kt

@@ -0,0 +1 @@
+// Empty file to satisfy test framework requirements

idea/idea-completion/testData/handlers/multifile/FileRefInStringLiteralTab.kt.after

@@ -0,0 +1,3 @@
+fun foo() {
+    val s = "foo.txt"
+}

idea/idea-completion/tests/org/jetbrains/kotlin/idea/completion/test/MultiFileJvmBasicCompletionTestGenerated.java

@@ -125,6 +125,18 @@ public class MultiFileJvmBasicCompletionTestGenerated extends AbstractMultiFileJ
         doTest(fileName);
     }
 
+    @TestMetadata("FileRefInStringLiteral")
+    public void testFileRefInStringLiteral() throws Exception {
+        String fileName = KotlinTestUtils.navigationMetadata("idea/idea-completion/testData/basic/multifile/FileRefInStringLiteral/");
+        doTest(fileName);
+    }
+
+    @TestMetadata("FileRefInStringLiteralNoPrefix")
+    public void testFileRefInStringLiteralNoPrefix() throws Exception {
+        String fileName = KotlinTestUtils.navigationMetadata("idea/idea-completion/testData/basic/multifile/FileRefInStringLiteralNoPrefix/");
+        doTest(fileName);
+    }
+
     @TestMetadata("GroovyClassNameCompletionFromDefaultPackage")
     public void testGroovyClassNameCompletionFromDefaultPackage() throws Exception {
         String fileName = KotlinTestUtils.navigationMetadata("idea/idea-completion/testData/basic/multifile/GroovyClassNameCompletionFromDefaultPackage/");

idea/idea-completion/tests/org/jetbrains/kotlin/idea/completion/test/handlers/CompletionMultifileHandlerTest.kt

@@ -85,6 +85,14 @@ class CompletionMultiFileHandlerTest : KotlinCompletionTestCase() {
         doTest('\t', "TestBundle.properties")
     }
 
+    fun testFileRefInStringLiteralEnter() {
+        doTest('\n', "foo.txt", "bar.txt")
+    }
+
+    fun testFileRefInStringLiteralTab() {
+        doTest('\t', "foo.txt", "bar.txt")
+    }
+
     fun testNotImportedExtension() {
         doTest()
     }