hints: merge RRs instead of replacing them
We had this behavior in 5.x.
- Lua level: affects hints.set() and hints['name'] and hints.add_hosts()
- YAML level: /local-data/addresses and /local-data/addresses-files
I considered various approaches when writing this. This one won because in /etc/hosts like files a name can be repeated with arbitrary lines in between, and users can reasonably expect it to collect all addresses.
Fixes #808 (closed)
Edited by Vladimír Čunát