Fixes #29385: Add /shrug and /tableflip commands

What does this MR do?

This adds two new slash commands /shrug and /tableflip

• /shrug prepends the comment with ¯\_(ツ)_/¯
• /tableflip appends the comment with (╯°□°)╯︵ ┻━┻

Are there points in the code the reviewer needs to double check?

I guess I think it's probably fine. ¯\_(ツ)_/¯

Why was this MR needed?

Issue #29385 (closed) suggested that it'd be nice to have a shrug slash command.

Screenshots (if relevant)

Does this MR meet the acceptance criteria?

• Changelog entry added, if necessary
• Documentation created/updated
• API support added
• Tests
  • Added for this feature/bug
  • All builds are passing
• Conform by the merge request performance guides
• Conform by the style guides
• Branch has no merge conflicts with master (if it does - rebase it please)
• Squashed related commits together

What are the relevant issue numbers?

#29385 (closed)