[cabol#178] External cache-key references on cacheable decorator

lib/nebulex.ex

@@ -6,10 +6,12 @@ defmodule Nebulex do
       Via the cache, we can put, get, update, delete and query existing entries.
       A cache needs an adapter to communicate to the in-memory data store.
 
-    * `Nebulex.Caching` - decorators provide an elegant way of annotating
-      functions to be cached or evicted. By means of these decorators, it is
-      possible the implementation of cache usage patterns like **Read-through**,
-      **Write-through**, **Cache-as-SoR**, etc.
+    * `Nebulex.Caching` - Declarative annotation-based caching via
+      **`Nebulex.Caching.Decorators`**. Decorators provide n elegant way of
+      annotating functions to be cached or evicted. Caching decorators also
+      enable the usage and/or implementation of cache usage patterns like
+      **Read-through**, **Write-through**, **Cache-as-SoR**, etc.
+      See [Cache Usage Patters Guide](http://hexdocs.pm/nebulex/cache-usage-patterns.html).
 
   In the following sections, we will provide an overview of those components and
   how they interact with each other. Feel free to access their respective module

lib/nebulex/cache.ex

@@ -563,7 +563,7 @@ defmodule Nebulex.Cache do
 
   @doc """
   Returns the default key generator applied only when using
-  **"declarative annotation-based caching"** via `Nebulex.Caching`.
+  **"declarative annotation-based caching"** via `Nebulex.Caching.Decorators`.
 
   Sometimes you may want to set a different key generator when using
   declarative caching. By default, the key generator is set to
@@ -572,7 +572,8 @@ defmodule Nebulex.Cache do
 
       use Nebulex.Cache, default_key_generator: MyKeyGenerator
 
-  See `Nebulex.Caching` and `Nebulex.Caching.KeyGenerator` for more information.
+  See `Nebulex.Caching.Decorators` and `Nebulex.Caching.KeyGenerator`
+  for more information.
   """
   @callback __default_key_generator__ :: Nebulex.Caching.KeyGenerator.t()