chore(tvix/docs): move from doc

Most other docs folders in the repo are called `doc` too, let's make
this consistent.

Change-Id: Icd712429b51763076548c977321e370f2a77877e
Reviewed-on: https://cl.tvl.fyi/c/depot/+/2741
Tested-by: BuildkiteCI
Reviewed-by: tazjin <mail@tazj.in>

tvix/docs/default.nix

@@ -0,0 +1,39 @@
+{ pkgs, lib, ... }:
+
+let
+
+  tl = pkgs.texlive.combine {
+    inherit (pkgs.texlive) scheme-medium wrapfig ulem capt-of
+    titlesec preprint enumitem paralist ctex environ svg
+    beamer trimspaces zhnumber changepage framed pdfpages
+    fvextra minted upquote ifplatform xstring;
+  };
+
+  csl = pkgs.fetchurl {
+    name = "numeric.csl";
+    url = "https://gist.githubusercontent.com/bwiernik/8c6f39cf51ceb3a03107/raw/1d75c2d62113ffbba6ed03a47ad99bde86934f2b/APA%2520Numeric";
+    sha256 = "1yfhhnhbzvhrv93baz98frmgsx5y442nzhb0l956l4j35fb0cc3h";
+  };
+
+in pkgs.stdenv.mkDerivation {
+  pname = "tvix-doc";
+  version = "0.1";
+
+  src = lib.cleanSource ./.;
+
+  CSL = csl;
+
+  nativeBuildInputs = [
+    pkgs.pandoc
+    pkgs.plantuml
+    tl
+  ];
+
+  installPhase = ''
+    runHook preInstall
+    mkdir -p $out
+    cp -v *.html $out/
+    runHook postSubmit
+  '';
+
+}