readme: add ghostty terminal ref

[huskyjp]

Overview

Added a ghostty terminal link support which already merged here: aws/amazon-q-developer-cli#335

[withfig-bot]

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[withfig-bot]

No files changed ☑️

[withfig-bot]

Hello @huskyjp,
thank you very much for creating a Pull Request!
Here is a small checklist to get this PR merged as quickly as possible:

• Do all subcommands / options which take arguments include the args property (args: {})?
• Are all options modular? E.g. -a -u -x instead of -aux
• Have all other checks passed?

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