Pull request: Configuration: doc autohost_tld

Merge in DNS/adguard-home-wiki from 2393-autohost-tld to master

Squashed commit of the following:

commit 7bdbf832c3bf3d6e431faf82e949d131987d53ac
Author: Ainar Garipov <A.Garipov@AdGuard.COM>
Date:   Wed Mar 24 19:21:55 2021 +0300

    Configuration: doc autohost_tld

Configuration.md

@@ -223,6 +223,10 @@ Settings are stored in [YAML format](https://en.wikipedia.org/wiki/YAML), possib
     - `cache_time` — Safe Browsing, Safe Search, Parental Control cache TTL
     - `max_goroutines` — Max. number of parallel goroutines for processing incoming requests
     - `ipset` — List of domain-ipset_name associations for adding IP addresses of the specified domain names to an ipset list. Syntax: `DOMAIN[,DOMAIN].../IPSET_NAME[,IPSET_NAME]...`. IPv4 addresses are added to an ipset list with `ipv4` family, IPv6 addresses - to `ipv6` ipset list. ipset list must exist. This setting is supported on Linux only. This feature is similar to `--ipset` in dnsmasq.
+    - `autohost_tld` (**since v0.106.0**) — The top-level domain that AdGuard
+      Home uses for known internal hosts.  The default value, which is also set
+      when this value is empty, is `lan`.  So, if you have a machine called
+      `myhost` in your network, its automatic hostname will be `myhost.lan`.
 - `filters` — List of filters, each filter has the following values:
   - `enabled` — Current filter's status (enabled/disabled).
   - `url` — URL pointing to the filter contents (filtering rules).