Update two outdated statements in the modules and plugins docs (#521)

* Remove the 2.1 warning wrt plugins

* More than 2 modules exist now

development/cpp/custom_modules_in_cpp.rst

@@ -12,8 +12,9 @@ functionality at every level without modifying the core, which can be
 split for use and reuse in different modules.
 
 Modules are located in the ``modules/`` subdirectory of the build system.
-By default, two modules exist, GDScript (which, yes, is not part of the
-core engine), and the GridMap. As many new modules as desired can be
+By default, many different modules exist, such as GDScript (which, yes,
+is not part of the base engine), the Mono runtime, a regular expressions
+module, and others. As many new modules as desired can be
 created and combined, and the SCons build system will take care of it
 transparently.
 

development/plugins/making_plugins.rst

@@ -3,11 +3,6 @@
 Making Plugins
 ==============
 
-.. Remove this warning when 2.1 is release
-
-*Important:* This tutorial applies only to the upcoming version 2.1.
-
-
 About Plugins
 ~~~~~~~~~~~~~