add typst to dependencies

README.md

@@ -22,6 +22,7 @@ Either use the provided nix flake to take care of everything or ensure the
 following is installed:
 
 - [lilypond](https://lilypond.org)
+- [typst](https://github.com/typst/typst) binary
 - a tex installation (for example [TeX Live](https://www.tug.org/texlive/)) with
   the _pdfcrop_ and _pdfjam_ commands
 - [gnu make](https://www.gnu.org/software/make/) (might work with other makes,

flake.nix

@@ -26,6 +26,7 @@
               timidity
               source-han-serif
               source-han-sans
+              typst
             ];
           };
       }