Fix typo in WindowBar parser - fixes #543

[popey]

👋 Hello!

This corrects a typo in the WindowBar parser. fixes #543

Tested locally:

Before

$ vhs test.tape
File: test.tape
  3 │ Set WindowBar RingsRight
                    ^^^^^^^^^^ RingsRight is not a valid bar style.

parser: 1 error(s)
recording failed

After

./vhs ./test.tape
File: ./test.tape
Output .gif demo.gif
Set WindowBar RingsRight
Set FontSize 46
Set Width 1200
Set Height 600
Type echo Welcome to VHS!
Sleep 500ms
Enter 1
Sleep 5s
Creating demo.gif...
Host your GIF on vhs.charm.sh: vhs publish <file>.gif