Use luals-stubs as the source of truth for docs, instead of maintaining

separate docs stubs

Includes introducing a cool new script to turn lua-language-server's
json output into markdown documentation.

luals-stubs/backstack.lua

@@ -1,11 +1,20 @@
 --- @meta
 
+--- The `backstack` module contains functions that can be used to implement a
+--- basic stack-based navigation hierarchy. See also the `screen` module, which
+--- provides a class prototype meant for use with this module.
 --- @class backstack
 local backstack = {}
 
---- @param constructor function
-function backstack.push(constructor) end
+--- Displays the given screen to the user. If there was already a screen being
+--- displayed, then the current screen is removed from the display, and added
+--- to the backstack.
+--- @param screen screen The screen to display.
+function backstack.push(screen) end
 
+--- Removes the current screen from the display, then replaces it with the
+--- screen that is at the top of the backstack. This function does nothing if
+--- there are no other screens in the stack.
 function backstack.pop() end
 
 return backstack