There is a lot of hyperbole in tech journalism, just as there is in other journalism. While Windows 10 does indeed collect a lot of data about you, some of it being the result of key strokes, it does not come with a keylogger in any traditional sense of the word.
And at the end of the article, there is this clarification:
Does this mean Microsoft is planning to use Windows 10 to swipe everyone's online banking passwords? The chances are slim to none – although if you do your online banking on a prerelease test version of Windows with an experimental build of Internet Explorer, you deserve what you get.
On to the second article. The author focus on this quote from the privacey policy:
When you interact with your Windows device by speaking, writing (handwriting), or typing, Microsoft collects speech, inking, and typing information—including information about your Calendar and People (also known as contacts)...
While this may have privacy implications that you dislike, it is not the same as a traditional keylogging. Recording keystrokes to analyze e.g. word frequenzies is not the same as storing every single keystroke. And I bet they don't do it when you type in password fields...
This article posted in comments by John Wu might also be helpful:
Look, the Windows 10 Technical Preview is an instrumented version. It collects information about your use of the product, including some text and voice input, and returns some of that data to Microsoft for use in tuning performance and improving voice recognition and spell-checking.
That's a far cry from a keylogger, which is a surveillance tool that indiscriminately collects every keystroke on a PC and transmits it (usually surreptitiously) to a remote location.
So you will not be able to recover your lost password by leveraging an alleged built in keylogger.