update genbinding doc

Signed-off-by: Ava Hahn <ava@sunnypup.io>

snippets/genbind.rls

@@ -27,8 +27,23 @@
 
 The point is to be able to autogenerate bindings for shell commands.
 Example: (eval ((gen-binding (q ls) '-l') ('-a')))
-     Or: (def gcommit 'shortcut for git commit -s -m <arg>
+     Or: (def gcommit 'use: (gcommit my-message)'
-           (lambda (arg) (eval ((gen-binding (q git) 'commit') ('-s' '-m' arg)))))"
+           (lambda (arg) (eval ((gen-binding 'git' 'commit') ('-s' '-m' arg)))))
+
+
+Or, a more advanced use:
+  (def -git-opts 'all subcommands for guix'
+    ('add' 'push' 'stash'))
+
+  ;; define global functions for each subcommand
+  (let ((gx-iter (pop -git-opts)))
+    (while (gt? (len gx-iter) 1)
+      (let ((subc (car gx-iter))
+            (rest (cdr gx-iter)))
+        (def (concat 'g-' subc)
+          'subcommand binding for git. takes a list of args'
+          (lambda (args) (eval ((gen-binding 'git' subc) args))))
+        (set (q gx-iter) (pop rest)))))"
    (sym subcommand)
    (let ((lam ((q lambda)
                (cons (q args))