Since TBC 2.4.0 you’re supposed to be able to link quests in chat, but that functionality is still missing as of 3.4.1. Trying to link a quest simply writes it out as plain text.
https://wowpedia.fandom.com/wiki/Patch_2.4.0
- You can now link quests into the chat log by Shift-Clicking on the quest name in the quest log.