Document that Copilot coding agent requires code to be stored on GitHub (#56764)

Author: timrogers

content/copilot/concepts/about-copilot-coding-agent.md

@@ -134,6 +134,7 @@ Users can include hidden messages in issues assigned to {% data variables.produc
 * **{% data variables.product.prodname_copilot_short %} doesn't account for content exclusions**. Content exclusions allow administrators to configure {% data variables.product.prodname_copilot_short %} to ignore certain files. When using {% data variables.copilot.copilot_coding_agent %}, {% data variables.product.prodname_copilot_short %} will not ignore these files, and will be able to see and update them. See [AUTOTITLE](/copilot/managing-copilot/configuring-and-auditing-content-exclusion/excluding-content-from-github-copilot).
 * **{% data variables.copilot.copilot_coding_agent %} does not apply the "Suggestions matching public code" policy**. {% data variables.product.prodname_copilot_short %} may still produce suggestions matching public code, even if the "Suggestions matching public code" policy is set to "Block." If this happens, {% data variables.product.prodname_copilot_short %} will not provide code references pointing to the original source of the code. See [AUTOTITLE](/copilot/managing-copilot/managing-copilot-as-an-individual-subscriber/managing-your-copilot-plan/managing-copilot-policies-as-an-individual-subscriber#enabling-or-disabling-suggestions-matching-public-code).
 * **{% data variables.copilot.copilot_coding_agent %} is not available in {% data variables.enterprise.data_residency %}**. The agent is only available in {% data variables.product.prodname_dotcom_the_website %}.
+* **{% data variables.copilot.copilot_coding_agent %} only works with repositories hosted on {% data variables.product.github %}**. If your repository is stored using a different code hosting platform, {% data variables.product.prodname_copilot_short %} won't be able to work on it.
 
 ## Hands-on practice
 

data/reusables/gated-features/copilot-coding-agent.md

@@ -1 +1 @@
-{% data variables.copilot.copilot_coding_agent %} is available with the {% data variables.copilot.copilot_pro %}, {% data variables.copilot.copilot_pro_plus %}, {% data variables.copilot.copilot_for_business %} and {% data variables.copilot.copilot_enterprise %} plans. The agent is available in all repositories, except where it has been explicitly disabled and repositories owned by {% data variables.enterprise.prodname_managed_users %}.
+{% data variables.copilot.copilot_coding_agent %} is available with the {% data variables.copilot.copilot_pro %}, {% data variables.copilot.copilot_pro_plus %}, {% data variables.copilot.copilot_for_business %} and {% data variables.copilot.copilot_enterprise %} plans. The agent is available in all repositories stored on {% data variables.product.github %}, except repositories owned by {% data variables.enterprise.prodname_managed_users %} and where it has been explicitly disabled.