Fix parser error test offsets - correct positions for JSON keyword errors

Co-authored-by: llali <17187348+llali@users.noreply.github.com>

Author: Copilot

Test/SqlDom/ParserErrorsTests.cs

@@ -4420,11 +4420,11 @@ public void CreateJsonIndexStatementErrorTest()
             // Test that UNIQUE and CLUSTERED/NONCLUSTERED are not allowed with JSON indexes in TSql170
             TSql170Parser parser170 = new TSql170Parser(true);
             ParserTestUtils.ErrorTest(parser170, "CREATE UNIQUE JSON INDEX idx1 ON table1 (jsonColumn)",
-                new ParserErrorInfo(19, "SQL46010", "INDEX"));
+                new ParserErrorInfo(14, "SQL46010", "JSON"));
             ParserTestUtils.ErrorTest(parser170, "CREATE CLUSTERED JSON INDEX idx1 ON table1 (jsonColumn)",
-                new ParserErrorInfo(22, "SQL46010", "INDEX"));
+                new ParserErrorInfo(17, "SQL46010", "JSON"));
             ParserTestUtils.ErrorTest(parser170, "CREATE NONCLUSTERED JSON INDEX idx1 ON table1 (jsonColumn)",
-                new ParserErrorInfo(26, "SQL46010", "INDEX"));
+                new ParserErrorInfo(20, "SQL46010", "JSON"));
 
             // Test malformed JSON Index syntax in TSql170
             // Missing column specification