tsconfig.json does have code highlighting even though regular *.json files do

When I create tsconfig.json file, it does not have the regular json highlighting.

I've tried deleting and redoing the file,  and erasing my .idea folder. I've also just started a new project and made a new file there to see if there was something wrong with the project.

In one of my projects I did make a .tsconfigrc file, but I don't know if that matters anyway.

I've included a couple of pictures. One shows the regular *.json highlighting, and the other shows how tsconfig.json is not.