Update telling-git-about-your-signing-key.md

[jackverstraate]

Edited the ZSH shell command to use the proper denotation for the TTY variable.

Why:

This will fix GPG failing to sign commits/tags on macOS as it now properly able to reference the TTY variable.

What's being changed (if available, include any code snippets, screenshots, or gifs):

$(tty) --> $TTY

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• A subject matter expert (SME) has reviewed the technical accuracy of the content in this PR. In most cases, the author can be the SME. Open source contributions may require an SME review from GitHub staff.
• The changes in this PR meet the docs fundamentals that are required for all content.
• All CI checks are passing and the changes look good in the review environment.

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Source	Review	Production	What Changed
authentication/managing-commit-signature-verification/telling-git-about-your-signing-key.md	fpt ghec ghes@ 3.17 3.16 3.15 3.14	fpt ghec ghes@ 3.17 3.16 3.15 3.14

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🤖 This comment is automatically generated.

[Sharra-writes]

@jackverstraate Thanks for opening a PR! Copilot says this change is incorrect, but Copilot is far from infallible, so I'm getting a second (human) opinion.

[Sharra-writes]

@jackverstraate I looked into this a little more, and you don't provide exact details about what you're doing, but I'm told the errors likely have something to do with the way you're setting up your variables. The article as its written isn't wrong, even if it doesn't work for your preferred setup. Because of that, I'm going to close this PR.