Tried opening many markdown files and editor froze then laptop

[stuaxo]

I grabbed retext so I could read about 220 files I exported to markdown.
Once I had the files I tried opening them all with retext.

First the editor froze many times, with GNOME saying it was not responding.
After a while the laptop got into a strange state (sometimes the it seems to do this with AMD) - which seems to happen when I use either all the RAM or CPU, it can make the graphics drivers unhappy.

The laptop isn't super specced, but should be fine: AMD Ryzen 3700u 16gb with 4 cores, 8 threads, NVME.

Whatever happens when files are opened should probably happen in the background so the editor doesn't become unresponsive.

On the subject of using all the resources (which is what will have triggered the other behaviour I saw) - it would be good to have some sort of throttling; I'm not sure what was happens during the opening of the files, but that should probably only run a certain amount of those at once, probably not more than the amount of cores in the machine, but maybe less.