Merge pull request #1947 from Mikaela/docs-op-invite

MANUAL.md: clarify appropiate privs for invite

docs/MANUAL.md

 
 ### +i - Invite-Only
 
-If this channel mode is set on a channel, users will only be able to join if someone has `/INVITE`'d them first.
+If this channel mode is set on a channel, users will only be able to join if a channel operator has `/INVITE`'d them first.
 
 To set a channel to invite-only:
 
     /MODE #test +i
 
-To unset the mode and let anyone join:
+To unset the mode and let anyone join (and invite):
 
     /MODE #test -i
 
 
 This prefix means that the given user is an operator on the channel (chanop, for short). For example, if `@ruby` is on a channel, then **ruby** is an op.
 
-Chanops are the default type of channel moderators. They can change the channel modes, ban/kick users, and add or remove chanop (or lower) privileges from users.
+Chanops are the default type of channel moderators. They can change the channel modes, ban/kick users, and add or remove chanop (or lower) privileges from users. They can also invite users to invite-only channels.
 
 ### +h (%) - Halfop