Why does the Kind column show the Chinese characters 文件 for Markdown files?
The reason you have that text is two-fold:


An application you installed (might even be Sublime Text) defined a new type - namely kMDItemContentType of "com.unknown.md"
CoreServices read the localized description from that app and makes it available to Finder. 


To fix this, fix, update or uninstall the app that defined com.unknown.md as a core file type paying attention to the localized text it provides to Finder to display.



Tracking this down will take a little sleuthing since you haven't disclosed the identity of the app that has exerted control as the default app to open that file type. That should be shown in the cropped portion of the get info you showed in your question.

Also, there are layers of programs that can "ask" to open a file type, and layers of file type on each file (shown as kMDItemContentTypeTree) - so depending on the order in which you install apps, the same Mac with the same apps installed might get different results based on the order in which the apps installed, and how you use the apps and if you change and of the spotlight / CoreServices defaults.

To pick this apart, I use a tool lsregister to dump the entire launch services database and parse out items. It's a bit painstaking, but you can always do this if you can't find the app you installed, right click on the icon in question and use Open With... to change the default app to one you prefer how it shows in Finder. Also - now that you know which app Finder is trusting to "name" that new file type/kind - you can open a support request with that software maker to change what's displayed - they likely made a bug in the localization and listed Chinese text for the UK English localized text.