delete some dead code

This is a holdover from the days of bifold text.

commands.lua

@@ -129,8 +129,7 @@ end
 
 function navigate_to_file(s)
   move_candidate_to_front(s)
-  local candidate = guess_source(s..'.lua')
-  source.switch_to_file(candidate)
+  source.switch_to_file(s..'.lua')
   reset_file_navigator()
 end
 

log_browser.lua

@@ -35,7 +35,6 @@ function log_browser.parse(State)
       if rest then
         line.data = rest
       end
-      line.filename = guess_source(line.filename)
       line.line_number = tonumber(line.line_number)
       if line.data:sub(1,1) == '{' then
         local data = json.decode(line.data)
@@ -75,15 +74,6 @@ function table.shallowcopy(x)
   return {unpack(x)}
 end
 
-function guess_source(filename)
-  local possible_source = filename:gsub('%.lua$', '%.splua')
-  if file_exists(possible_source) then
-    return possible_source
-  else
-    return filename
-  end
-end
-
 function log_browser.draw(State, hide_cursor)
   assert(#State.lines == #State.line_cache)
   local mouse_line_index = log_browser.line_index(State, App.mouse_x(), App.mouse_y())