[admin] Make issue template comments actual markdown comments

[learn-build-service-prod[bot]]

Learn Build status updates of commit 6248ad5:

:white_check_mark: Validation status: passed

File	Status	Preview URL	Details
.github/ISSUE_TEMPLATE/1_documentation-issue.md	:white_check_mark:Succeeded
.github/ISSUE_TEMPLATE/2_sample-request.md	:white_check_mark:Succeeded

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