[rfced] Section 6.1: Because "primary" is used instead of

[ekr-cibot]

[rfced] Section 6.1: Because "primary" is used instead of
"first", should "second" in the next sentence be "secondary"?

Original:
The primary mechanism is for an authorized member of the group to
send a Commit that adds or removes other members. The second
mechanism is an "external join": A member of the group publishes
certain information about the group, which a new member can use to
construct an "external" Commit message that adds the new member to
the group.

[ekr-cibot]

tagging @lbartholomew-rpc for awareness