Enable math characters in vector (node) names for command alter

Replace ft_getpnames() by ft_getpnames_quotes().

src/frontend/device.c

@@ -1251,7 +1251,7 @@ com_alter_common(wordlist *wl, int do_model)
     words = eqword->wl_next;
     /* skip next line if words is a vector */
     if (!eq(words->wl_word, "["))
-        names = ft_getpnames(words, FALSE);
+        names = ft_getpnames_quotes(words, FALSE);
     else
         names = NULL;