fix: bump EXPECTED_LEN to 28 after merging Julia + R

Author: carlos-alm

crates/codegraph-core/src/parser_registry.rs

@@ -277,7 +277,7 @@ mod tests {
         // Because both checks require the same manual update, they reinforce
         // each other: a developer who updates the match is reminded to also
         // update `all()` and this count.
-        const EXPECTED_LEN: usize = 27;
+        const EXPECTED_LEN: usize = 28;
         assert_eq!(
             LanguageKind::all().len(),
             EXPECTED_LEN,