Docs: fix markdown in various files, update the README mildly

sky/specs/modules.md

 Sky module system
 =================
 
 This document describes the Sky module system.
 
 Overview
 --------
 
 The Sky module system is based on the ```import``` element. In its
 most basic form, you import a module as follows:
@@ skipping 12 matching lines @@
 finished parsing, the document waits until its list of outstanding
 dependencies is empty before the module it represents is marked
 complete.
 
 Module API
 ----------
 
 Within a script in a module, the ```module``` identifier is bound to
 the ```Module``` object that represents the module:
 
-```
+```javascript
 interface Module : EventTarget {
   constructor (Application application, Document document); // O(1)
   attribute any exports; // O(1) // defaults to the module's document
   readonly attribute Document document; // O(1) // the module's document
   readonly attribute Application application; // O(1)
 }
 ```
 
 ### Exporting values ###
 
@@ skipping 24 matching lines @@
 Where ```name_1``` through ```name_n``` are the names bound to the
 various named imports in the script element's document,
 ```source_code``` is the text content of the script element,
 ```source_module`` is the ```Module``` object of the script element's
 module, and ```value_1``` through ```value_n``` are the values
 exported by the various named imports in the script element's
 document.
 
 When an import fails to load, the ```as``` name for the import gets
 bound to ```undefined```.