Always end interpolation even if ) is present

When parsing the end of an interpolation segment,
even if there is a closing `)` present, the lexer
may still think it's inside a nested position in
an interpolated segment. As such, make sure to
always tell it to move back to string literal
mode for better diagnostics.

Author: hamishknight

Sources/SwiftParser/StringLiterals.swift

@@ -490,7 +490,7 @@ extension Parser {
           unexpectedBeforeRightParen.append(self.consumeAnyToken())
         }
         let rightParen = self.expectWithoutRecovery(.rightParen)
-        if rightParen.isMissing, case .inStringInterpolation = self.currentToken.cursor.currentState {
+        if case .inStringInterpolation = self.currentToken.cursor.currentState {
           // The parser has more knowledge that we have reached the end of the
           // string interpolation now, even if we haven't seen the closing ')'.
           // For example, consider the following code

Tests/SwiftParserTest/ExpressionTests.swift

@@ -1656,13 +1656,12 @@ final class StatementExpressionTests: XCTestCase {
   func testUnterminatedInterpolationAtEndOfMultilineStringLiteral() {
     AssertParse(
       #"""
-      """\({(1️⃣})
-      2️⃣"""3️⃣
+      """1️⃣\({(2️⃣})
+      """
       """#,
       diagnostics: [
-        DiagnosticSpec(locationMarker: "1️⃣", message: "expected value and ')' to end tuple"),
-        DiagnosticSpec(locationMarker: "2️⃣", message: #"unexpected code '"""' in string literal"#),
-        DiagnosticSpec(locationMarker: "3️⃣", message: #"expected '"""' to end string literal"#),
+        DiagnosticSpec(locationMarker: "1️⃣", message: "multi-line string literal content must begin on a new line"),
+        DiagnosticSpec(locationMarker: "2️⃣", message: "expected value and ')' to end tuple"),
       ]
     )
   }

Tests/SwiftParserTest/translated/UnclosedStringInterpolationTests.swift

@@ -111,7 +111,7 @@ final class UnclosedStringInterpolationTests: XCTestCase {
   func testSkipUnexpectedOpeningParensInStringLiteral() {
     AssertParse(
       #"""
-      "\(e 1️⃣H()2️⃣r
+      "\(e 1️⃣H()r2️⃣
       """#,
       diagnostics: [
         DiagnosticSpec(locationMarker: "1️⃣", message: "unexpected code 'H(' in string literal"),