Docs: remove invalid key from "update thread" example
Docs: remove invalid key from "update thread" example

The thread PUT route is only able to have the keys "add_tags" and "remove_tags" in the request
body, otherwise the response is a 400.

gale320/sync-engine,wakermahmud/sync-engine,ErinCall/sync-engine,closeio/nylas,jobscore/sync-engine,jobscore/sync-engine,wakermahmud/sync-engine,wakermahmud/sync-engine,PriviPK/privipk-sync-engine,jobscore/sync-engine,nylas/sync-engine,EthanBlackburn/sync-engine,PriviPK/privipk-sync-engine,gale320/sync-engine,EthanBlackburn/sync-engine,Eagles2F/sync-engine,Eagles2F/sync-engine,Eagles2F/sync-engine,PriviPK/privipk-sync-engine,nylas/sync-engine,nylas/sync-engine,ErinCall/sync-engine,closeio/nylas,EthanBlackburn/sync-engine,EthanBlackburn/sync-engine,nylas/sync-engine,gale320/sync-engine,closeio/nylas,closeio/nylas,Eagles2F/sync-engine,PriviPK/privipk-sync-engine,jobscore/sync-engine,Eagles2F/sync-engine,wakermahmud/sync-engine,EthanBlackburn/sync-engine,gale320/sync-engine,ErinCall/sync-engine,wakermahmud/sync-engine,PriviPK/privipk-sync-engine,ErinCall/sync-engine,ErinCall/sync-engine,gale320/sync-engine