Merge branch 'ms-sd-issue-description-doc' into 'master'

Adds ISSUE_DESCRPTION placeholder to service desk doc

See merge request !119770



Merged-by: Marcin Sedlak-Jakubowski <msedlakjakubowski@gitlab.com>
Approved-by: Rajendra Kadam <rkadam@gitlab.com>
Approved-by: Marcin Sedlak-Jakubowski <msedlakjakubowski@gitlab.com>
Reviewed-by: Marcin Sedlak-Jakubowski <msedlakjakubowski@gitlab.com>
Reviewed-by: Rajendra Kadam <rkadam@gitlab.com>
Co-authored-by: Marc Saleiko <msaleiko@gitlab.com>

doc/user/project/service_desk.md

@@ -101,6 +101,8 @@ visible in the email template. For more information, see
 
 #### Thank you email
 
+> `%{ISSUE_DESCRIPTION}` [introduced](https://gitlab.com/gitlab-org/gitlab/-/issues/223751) in GitLab 16.0.
+
 When a user submits an issue through Service Desk, GitLab sends a **thank you email**.
 
 To create a custom email template, in the `.gitlab/service_desk_templates/`
@@ -110,6 +112,7 @@ You can use these placeholders to be automatically replaced in each email:
 
 - `%{ISSUE_ID}`: issue IID
 - `%{ISSUE_PATH}`: project path appended with the issue IID
+- `%{ISSUE_DESCRIPTION}`: issue description based on the original email
 - `%{UNSUBSCRIBE_URL}`: unsubscribe URL
 - `%{SYSTEM_HEADER}`: [system header message](../admin_area/appearance.md#system-header-and-footer-messages)
 - `%{SYSTEM_FOOTER}`: [system footer message](../admin_area/appearance.md#system-header-and-footer-messages)
@@ -120,6 +123,8 @@ the response email does not contain the issue link.
 
 #### New note email
 
+> `%{ISSUE_DESCRIPTION}` [introduced](https://gitlab.com/gitlab-org/gitlab/-/issues/223751) in GitLab 16.0.
+
 When a user-submitted issue receives a new comment, GitLab sends a **new note email**.
 
 To create a custom email template, in the `.gitlab/service_desk_templates/`
@@ -129,6 +134,10 @@ You can use these placeholders to be automatically replaced in each email:
 
 - `%{ISSUE_ID}`: issue IID
 - `%{ISSUE_PATH}`: project path appended with the issue IID
+- `%{ISSUE_DESCRIPTION}`: issue description at the time email is generated.
+  If a user has edited the description, it might contain sensitive information that is not intended
+  to be delivered to external participants. Use this placeholder only if you never modify
+  descriptions or your team is aware of the template design.
 - `%{NOTE_TEXT}`: note text
 - `%{UNSUBSCRIBE_URL}`: unsubscribe URL
 - `%{SYSTEM_HEADER}`: [system header message](../admin_area/appearance.md#system-header-and-footer-messages)