Fix wrong wrapping of quote tokens around identifiers

Author: kimdv

Sources/SwiftParser/StringLiterals.swift

@@ -487,7 +487,7 @@ extension Parser {
       // string literal.
       guard currentToken.leadingTriviaText.isEmpty else { break }
 
-      if let stringSegment = self.consume(if: .stringSegment) {
+      if let stringSegment = self.consume(if: .stringSegment, .identifier) {
         segments.append(.stringSegment(RawStringSegmentSyntax(content: stringSegment, arena: self.arena)))
       } else if let backslash = self.consume(if: .backslash) {
         let (unexpectedBeforeDelimiter, delimiter) = self.parsePoundDelimiter(.rawStringDelimiter, matching: openDelimiter)

Tests/SwiftParserTest/AttributeTests.swift

@@ -422,12 +422,19 @@ final class AttributeTests: XCTestCase {
 
     assertParse(
       """
-      @_expose(Cxx, 1️⃣baz) func foo() {}
+      @_expose(Cxx, 1️⃣baz2️⃣) func foo() {}
       """,
       diagnostics: [
-        DiagnosticSpec(message: "expected string literal to end @_expose arguments", fixIts: ["insert string literal"]),
-        DiagnosticSpec(message: "unexpected code 'baz' in attribute"),
-      ]
+        DiagnosticSpec(locationMarker: "1️⃣",
+                       message: #"expected '"' in string literal"#,
+                       fixIts: [#"insert '"'"#]),
+        DiagnosticSpec(locationMarker: "2️⃣",
+                       message: #"expected '"' to end string literal"#,
+                      fixIts: [#"insert '"'"#]),
+      ],
+      fixedSource:"""
+      @_expose(Cxx, "baz") func foo() {}
+      """
     )
   }