#2980 fix cors doc (#3013)

docs/tendermint-core/configuration.md

@@ -81,10 +81,10 @@ laddr = "tcp://0.0.0.0:26657"
 cors_allowed_origins = []
 
 # A list of methods the client is allowed to use with cross-domain requests
-cors_allowed_methods = [HEAD GET POST]
+cors_allowed_methods = ["HEAD", "GET", "POST"]
 
 # A list of non simple headers the client is allowed to use with cross-domain requests
-cors_allowed_headers = [Origin Accept Content-Type X-Requested-With X-Server-Time]
+cors_allowed_headers = ["Origin", "Accept", "Content-Type", "X-Requested-With", "X-Server-Time"]
 
 # TCP or UNIX socket address for the gRPC server to listen on
 # NOTE: This server only supports /broadcast_tx_commit