I forgot to mention that there hasn't been a formal lexilla release with Zig or Dart yet. This means that the changes in SciLexer.h for these lexers had to be added manually rather than using the real Lexilla's unmodified file. In any case, once Geany updates to the latest lexilla, it should be auto-fixed.
Fine, we have done that before until Geany updates of Lexilla and ctags which is usually slower than Lexilla and ctags releases ;-)