fix bug in gtrig parser and fix #200

offset when encountering '<<' was wrong @o_o@

Author: pchampin

turtle/src/parser/gtrig.rs

@@ -840,7 +840,7 @@ impl<I> GTriGSource<I> {
                     if txt[2..].starts_with('(') {
                         Ok((3, Some(GTriGState::TripleTerm)))
                     } else {
-                        Ok((3, Some(GTriGState::ReifiedTriple(true))))
+                        Ok((2, Some(GTriGState::ReifiedTriple(true))))
                     }
                 } else {
                     self.iriref(txt).map(|offset| (offset, None))

turtle/src/parser/gtrig/test.rs

@@ -674,6 +674,7 @@ fn nested_reified_triple() -> TestResult {
 #[test_case(r"<< :s :p :o ~ >> :a :b", 2; "1p1 triples with empty reified triple")]
 #[test_case(r"<< :s :p :o ~ :r >> :a :b", 2; "1p1 triples with explicitly reified triple")]
 #[test_case(r"{[ :p  :o ] .}", 1; " trig-syntax-bnode-08")]
+#[test_case(r":G {<<:s :p :o>> :q :z .}", 2; " trig12-rt-01")]
 fn count_triples(input: &str, exp: usize) -> TestResult {
     for i in [input, &format!("{input}\n # this is a comment")] {
         let data = format!("PREFIX : <ex:> {i}");