add hardware device descriptions to doc

most of the text is recycled and follows no particular format

doc/development.rst

@@ -41,6 +41,8 @@ that directory for console and monitor.  Use :command:`connect-vm`
 (also in the ``buildEnv`` environment) to connect to either of these
 sockets, and ^O to disconnect.
 
+.. _qemu-networking:
+
 Networking
 ==========
 

doc/hardware.nix

@@ -0,0 +1,18 @@
+with import <nixpkgs> {} ;
+
+let
+  devices =
+    builtins.readDir ../devices;
+  texts = lib.mapAttrsToList (n: t:
+    let d = import  ../devices/${n}/default.nix;
+        d' = { description = "no description for ${n}"; } // d;
+    in d'.description )
+    devices;
+in
+writeText "hwdoc" ''
+  Supported hardware
+  ##################
+
+  ${lib.concatStringsSep "\n\n" texts}
+
+''

doc/index.rst

@@ -11,6 +11,7 @@ Liminix
    admin
    development
    modules
+   hardware
 
 
 Indices and tables