Unescape single quote when converting to string template

idea/testData/intentions/convertToStringTemplate/unescapeSingleQuote.kt

@@ -0,0 +1,3 @@
+fun test(p: String): String {
+    return <caret>p + '\''
+}

idea/testData/intentions/convertToStringTemplate/unescapeSingleQuote.kt.after

@@ -0,0 +1,3 @@
+fun test(p: String): String {
+    return <caret>"$p'"
+}