As Linken points out, the Anet dev team isn't responsible for the management of the Guild wars 2 Wiki site, as with most Wiki's they are curated and by edited by players.
to try and address your issue, the chat command "/g1-5", "/g1-g5", and "/all guild" aren't valid command, the correct commands are
* /g (to talk to your currently represented guild)
* /g1 (to talk to your first guild)
* /g2 (to talk to your second guild)
* /g3 (to talk to your third guild)
* ect, seriously i'm not going to type them all out
you'll be able to see guild chat from any of the guilds you're currently a member off, with a colour change to the text depending on whether you are currently representing that guild or not(gold or pale gold, respectively). afaik, there is no chat command to talk to all your guilds at once, doing this would be very confusing , as you might accidentally use said command to have a conversation with one specific guild and have people from your other guild(s) see the message without any context.