start showing source menu file navigation state graphically

I'm a bit leery of going down this road:

- If there's a bug in how I render logs graphically that could be
  extremely misleading. Perhaps this suggests that the code to log
  things should be significantly simpler than the code that might be
  debugged. If writing the debug helper requires all my smarts I'm not
  smart enough to debug using the helper, etc. Given this idea, the fact
  that I'm copying production code into the logging helper is
  concerning.

- There's a question of what code it's ok for logging helpers to depend
  on. This is an issue shared with tests. I often implicitly (and
  without meaning to) assume the presence of some well-tested helpers
  when writing tests. If those helpers ever break I can get into a
  rabbit hole of debugging. This problem might be even more insidious
  with logging helpers that will give me no indication when they break.

Still and all, it's cool to see menus in my logs. Let's see if it's
useful.

1 files changed, 1 insertions, 0 deletions

diff --git a/source.lua b/source.lua
index 3b16b9d..13a66cd 100644
--- a/source.lua
+++ b/source.lua
@@ -1,4 +1,5 @@
 source = {}
+log_render = {}
 
 Editor_state = {}