feat(tvix/docs): add d2 support

This provides a nicer syntax to draw some diagrams.

Change-Id: I2ab580e61399a45f01ed422ee29382e860753ffa
Reviewed-on: https://cl.tvl.fyi/c/depot/+/11807
Autosubmit: flokli <flokli@flokli.de>
Tested-by: BuildkiteCI
Reviewed-by: yuka <yuka@yuka.dev>

tvix/docs/book.toml

@@ -15,6 +15,10 @@ command = "mdbook-admonish"
 after = ["links"] # ensure `{{#include}}` also gets processed
 assets_version = "3.0.2" # do not edit: managed by `mdbook-admonish install`
 
+[preprocessor.d2]
+command = "d2"
+after = ["links"] # ensure `{{#include}}` also gets processed
+
 [output]
 
 [output.html]

tvix/docs/default.nix

@@ -9,8 +9,10 @@ pkgs.stdenv.mkDerivation {
   src = lib.cleanSource ./.;
 
   nativeBuildInputs = [
+    pkgs.d2
     pkgs.mdbook
     pkgs.mdbook-admonish
+    pkgs.mdbook-d2
     pkgs.mdbook-plantuml
     pkgs.plantuml
   ];

tvix/shell.nix

@@ -30,6 +30,7 @@ pkgs.mkShell {
     pkgs.cargo-machete
     pkgs.cargo-expand
     pkgs.clippy
+    pkgs.d2
     pkgs.evans
     pkgs.fuse
     pkgs.go
@@ -37,6 +38,7 @@ pkgs.mkShell {
     pkgs.hyperfine
     pkgs.mdbook
     pkgs.mdbook-admonish
+    pkgs.mdbook-d2
     pkgs.mdbook-plantuml
     pkgs.nix_2_3 # b/313
     pkgs.pkg-config