Rename "Using the AssetLib" to "Using the Asset Library"

See #3969.

tutorials/assetlib/using_assetlib.rst

@@ -1,7 +1,7 @@
 .. _doc_using_assetlib:
 
-Using the AssetLib
-==================
+Using the Asset Library
+=======================
 
 On the website
 --------------
@@ -9,9 +9,9 @@ On the website
 Overview
 ~~~~~~~~
 
-As mentioned before, you can access the web frontend of the AssetLib
-on `Godot's official website <https://godotengine.org/asset-library/asset>`_, and this
-is what it looks like when you first visit it:
+As mentioned before, you can access the web frontend of the Asset Library on
+`Godot's official website <https://godotengine.org/asset-library/asset>`_.
+This is what it looks like when you first visit it:
 
 |image0|