Add (possibly out of date) docs on bindings

fixtures/bliss.config.js

@@ -2,6 +2,26 @@ let {file} = require('../bliss/bindings')
 
 module.exports = {
     code: 'addEventListener("fetch", ev => ev.respondWith(new Response(MESSAGE)))',
+    /*
+    Add your bindings to this object; the syntax is described here:
+    https://developers.cloudflare.com/workers/tooling/api/bindings/
+    with the following changes:
+
+    * the `key` is added to the value (must be an object) as `{'name': key}`,
+      replacing any existing `name` field
+    * if a `part` field is present in the value, an error is raised
+    * if a `file` field is present in the value its contents will be uploaded
+      alongside the script and exported as a global variable with the given
+      `name`; this only works for 'wasm_module' bindings
+    * the custom `bliss_asset` binding type allows uploading of arbitrary files
+      and folders exported as Uint8Arrays and (multi-level) maps thereof
+      respectively; read the docs of the assets module for more information
+
+    For convenience, you can use the exported `text`, `secret`, `kv` and `wasm`
+    helper functions to generate binding objects. You may also use `file` and
+    `dir`, but those bindings will only be available after you import the
+    `bliss-router/assets` module in the worker
+    */
     bindings: {
         MESSAGE: file('./fixtures/message.txt')
     }