Disallow invalid target names (#13140)
Disallow link-to-self (#13947).
Disallow linking to utility targets (#13902).
Merge topic 'tll-target-policies' into next

076cad0 Disallow linking to utility targets (#13902).
038f179 Disallow link-to-self (#13947).
4d2e803 Disallow invalid target names (#13140)