fix(treesitter): mark supertype nodes as named

**Problem:** Tree-sitter 0.24.0 introduced a new symbol type to denote
supertype nodes (`TSSymbolTypeSupertype`). Now, `language.inspect()`
(and the query `omnifunc`) return supertype symbols, but with double
quotes around them.

**Solution:** Mark a symbol as "named" based on it *not* being an
anonymous node, rather than checking that it is a regular node (which a
supertype also is not).

src/nvim/lua/treesitter.c

@@ -272,7 +272,7 @@ int tslua_inspect_lang(lua_State *L)
       continue;
     }
     const char *name = ts_language_symbol_name(lang, (TSSymbol)i);
-    bool named = t == TSSymbolTypeRegular;
+    bool named = t != TSSymbolTypeAnonymous;
     lua_pushboolean(L, named);  // [retval, symbols, is_named]
     if (!named) {
       char buf[256];