Resolve "gitlab-ce mattermost slash command for issue create needs better documentation"
What does this MR do?
Updates the documentation and the help command to be clearer, having the keys used to add a newline in chat clients (both Mattermost and Slack).
Are there points in the code the reviewer needs to double check?
- Are the available commands (via help) being formatted as <code>?
Why was this MR needed?
\n represents a new line character and doesn't communicate how the user should input the command. Also, to be correct, the documentation should use <kbd> instead of <code> for user input (see HTML5 specification)
Screenshots (if relevant)
| Mattermost | Docs | 
|---|---|
|  |  | 
Does this MR meet the acceptance criteria?
- 
Changelog entry added 
- 
Documentation created/updated 
- Tests
- 
All builds are passing 
 
- 
What are the relevant issue numbers?
Closes #25144 (closed)