feat: Don't parse expression if a line terminator is after return

The spec says that there if there is a line terminator after a return
that means an expression shouldn't be parsed.

JSS.Lib.UnitTests/ParserTests.cs

@@ -754,6 +754,24 @@ public void Parse_ReturnsReturnStatement_WithNoExpression_WhenProvidingReturn_Wi
         returnStatement!.ReturnExpression.Should().BeNull();
     }
 
+    [Test]
+    public void Parse_ReturnsReturnStatement_WithNoExpression_WhenProvidingReturn_WithNewLineThenExpression()
+    {
+        // Arrange
+        var parser = new Parser("return\n1");
+
+        // Act
+        var parsedProgram = ParseScript(parser);
+        var rootNodes = parsedProgram.ScriptCode;
+
+        // Assert
+        rootNodes.Should().HaveCount(2);
+
+        var returnStatement = rootNodes[0] as ReturnStatement;
+        returnStatement.Should().NotBeNull();
+        returnStatement!.ReturnExpression.Should().BeNull();
+    }
+
     [TestCaseSource(nameof(expressionToExpectedTypeTestCases))]
     public void Parse_ReturnsReturnStatement_WhenProvidingReturn(KeyValuePair<string, Type> expressionToExpectedType)
     {

JSS.Lib/Parser.cs

@@ -1705,8 +1705,8 @@ private ReturnStatement ParseReturnStatement()
     {
         _consumer.ConsumeTokenOfType(TokenType.Return);
 
-        // FIXME: return [no LineTerminator here] Expression[+In, ?Yield, ?Await] ;
-        // Don't parse an expression if there is a line terminator after the return
+        if (_consumer.IsLineTerminator()) return new ReturnStatement(null);
+
         TryParseExpression(out IExpression? returnExpression);
         return new ReturnStatement(returnExpression);
     }