Is your feature request related to a problem? Please describe.
When using wezterm record, there is no way to specify the output file.

Describe the solution you'd like
Add a new flag to the cli -o that accepts a path and write the asciicast to that file when that flag is present, otherwise, keep writing to a random filename in the temporary directory.

Describe alternatives you've considered
I can always look in the temp directory for the newest file that starts with the wezterm-recording prefix, but I think this is a better solution and easy to implement.

Additional context
If there are no issues with this feature, I'm willing to implement it myself, shouldn't be too hard.