docs(miner): regenerate env-reference.md for GITTENSORY_MINER_KILL_SWITCH (#5510)

#5198/#5500 added the env.GITTENSORY_MINER_KILL_SWITCH read in
lib/config-precedence.js without regenerating this generated doc,
so npm run miner:env-reference:check has been failing on main since.

Author: JSONbored