WSL access to CLI as admin
troubleshoot hardware issues
use bcdedit /set {bootmgr} path \EFI\ubuntu\grubx64.efi to fix bootloader issue
can disable fast startup
create a boot repair USB
We can't very well honestly call Linux 'new user friendly' with issues like this that many of us are familiar with. Another legit attitude to have is: "what do you expect for free?".
TBH, I rarely noticed the warning from nvim. I did get in the habit of learning when to use sudoedit though.
What should it do?
Suggest a practical solution like saving to another directory where it can later be moved. (Notepad in Windows will do this)
Ok, checked it and you're right, contrary to what I read. It does suggest in the error on Windows to save it to your documents instead at least.
You're right, some AI chat told me it wouldn't even open (by default). But at least it has a decent suggested solution in the error. 
Easiest to rember trick I know of, but most people aren't going to know it the first time they're hit with it. lol
By default, a text editor in Windows will not even open the file for you to edit if you do not have the privilege already.
A few, one account got their posts removed by the auto mod I have no control over.