Surface containing blob permalinks does not enclose with code blocks

[adlai]

Describe the bug
The message triggered by creation of an Issue that includes permalinks into code within the same repository does not render using a monospace code block in the displayed surface.

To Reproduce
Hoping that you're dogfooding, I will include one of these failures in the Slack message that should be triggered by the creation of this Issue... if so, scroll to the end of this message's surface.

If not, here are the steps to reproduce the behavior:

1. If you're not dogfooding, create a new issue in a repository that has slack notifications from the github integration enabled;
2. From the code browser of that repository, select some lines of code using the line numbers, and copy the permalink using the dropdown menu from the ellipsis that appears by the selection;
3. Submit the issue;
4. Open the Unreads view from app.slack.com and locate the offending message from the GitHub App.

Expected behavior
The lines of code quoted in the permalink should be enclosed in a multi-line code block.

Screenshots
My workstation does not currently allow screenshots.

Desktop (please complete the following information):

• OS: "btw I'm using Arch linux"
• Browser: Chromium
• Version: >= 131

Additional context
I first encountered this in a private Slack group, and I'm not currently in your organisation where this issue might demonstrate the bug, so please tell me if you neither see it below nor can reproduce it from my instructions above.

slack/.github/settings.yml

Lines 4 to 8 in 43774c2

	# The name of the repository. Changing this will rename the repository
	name: slack
	# A short description of the repository that will show up on GitHub
	description: Bring your code to the conversations you care about with the GitHub and Slack integration