📚 Spell out the request paths in the Inbox Messaging guide. The guide referred to the "Inbox Conversations endpoints" and "Inbox Messages endpoints" by link only, so a reader who did not click through never saw a path and had to guess one — and /inbox_conversations guesses 404, because the resources are nested (/inbox/conversations, /inbox/messages, /inbox/participants). Each section now shows its path where the action is described. Also fixes the "Bookings endpoints" link under Fetching an Inbox Conversation, which pointed at the Applications reference page instead of Bookings.
