[Feature Request] An ability to set Minecraft resolution

[La1eon]

As written in the title, it would be great to have an ability to enter (in pixels) width into one text box, height into another, next to the first one, and the Minecraft will launch with the specified resolution.

Without that feature if you want to play in windowed mode, you have to manually resize the Minecraft window every time you launch the game.

If you look at the screenshot below, you can see that unfortunately Minecraft versions 1.13 and above have additional things in their JSON file, while versions 1.12.2 and below don't have them, so it's quite complicated. To make matters worse, even the official Minecraft launcher has problem to properly set Minecraft resolution in its newer versions (1.13+).

Screenshot showing pretty-printed JSON file for Minecraft 1.14.4: