Moved some people to "past team members".
Fixed #23499 -- Error in built-in template tag "now" documentation
Fixed #23491 -- Clarified tutorial 3.

Thanks diek for the suggestion.
factorized create_fk_sql expression
factorized create_unique_sql expression
factorized delete_constraint_sql expression
added test for #23065
fixed #23065 -- quote constraint names in SQL
added 1.7.1 release notes for #23065