Fix CLI token set command

token.go

@@ -28,7 +28,14 @@ Usage:
 
 A token grants its own size and lifetime limits. Any limit left unset is
 inherited from the running server's defaults, so a token with no options
-behaves exactly like the anonymous tier but may claim vanity names.
+behaves exactly like the anonymous tier.
+
+"set" changes only what you name on the command line; anything you leave out
+keeps its current value. Give a limit an empty value to go back to inheriting
+the server's default, and turn a flag off with "=false":
+
+  uncensored-send token set friend --max-size=        inherit the default again
+  uncensored-send token set friend --vanity=false     revoke custom names
 
 Options:
 `
@@ -144,8 +151,8 @@ func (o *tokenOptions) register() *config.Set {
 	fs.String(&o.defExpiry, "default-expiry", "", "", "DURATION", "lifetime applied when this token does not ask for one")
 	fs.String(&o.chosen, "token", "t", "", "VALUE",
 		"use this token instead of a generated one; \"-\" reads it from standard input")
-	fs.Bool(&o.vanity, "vanity", "", false, "allow this token to claim custom names")
-	fs.Bool(&o.admin, "admin", "", false, "allow this token to delete anyone's files")
+	fs.Bool(&o.vanity, "vanity", "", false, "allow this token to claim custom names; --vanity=false revokes it")
+	fs.Bool(&o.admin, "admin", "", false, "allow this token to delete anyone's files; --admin=false revokes it")
 	return fs
 }