When the command help message is too long, it goes off the screen (depending on your window size) to the left due to the text aligning to the right. Instead, it should align to the left so that you can actually see the argument you are working with instead of what comes after it. See the screenshots provided, with one in a larger window so that you can see the entire command, and one being in a smaller window.

To test:

1. Type /team modify in chat but don't hit enter
2. Scale your window around to see that text aligns to right instead of left

Alternate test:

1. Type /advancement grant @s only
2. Scale your window to see text aligns to right instead of left