[docs] Typo

Hello, There's a typo in the 3.2.3 Documentation, The Python Tutorial, 6.2. Standard Modules. In line 3 of that section, there's a . missing right after the word "platform". The tutorial currently reads: "The set of such modules is a configuration option which also depends on the underlying platform For example, the winreg module is only provided on Windows systems." It should read: "The set of such modules is a configuration option which also depends on the underlying platform. For example, the winreg module is only provided on Windows systems." Best, -Gaston