[fix](docs) ipv6_cidr_to_range examples error on 4.x/dev (INET6_ATON -> to_ipv6) + reserved-word alias + truncated IPv6

[boluor]

Problem

On the dev (current) and 4.x trees, every example on
ipv6_cidr_to_range wraps the input in INET6_ATON('...'). The value
INET6_ATON returns is rejected by ipv6_cidr_to_range, so on both 4.1.1
and master the examples error instead of producing the documented output:

SELECT ipv6_cidr_to_range(INET6_ATON('2001:db8::1'), 64);
ERROR 1105 (HY000): errCode = 2, detailMessage = (127.0.0.1)[INVALID_ARGUMENT]Invalid IPv6 value

The 2.1/3.x docs use the working to_ipv6('...') form.

Fix (dev + 4.x, EN + ZH)

• INET6_ATON(...) → to_ipv6(...) so the examples run.
• as range → as `range` — range is a reserved keyword and otherwise
  fails to parse (mismatched input 'range').
• ZH /48 example: the expected max was truncated by one group
  (2001:db8:1:ffff:ffff:ffff:ffff → 2001:db8:1:ffff:ffff:ffff:ffff:ffff); the
  EN doc was already correct.

Verification

Ran every example on the page end-to-end against a live Apache Doris 4.1.1
cluster (dev tree verified against it too): all pass. The /48 range now returns
the full address on both languages:

SELECT ipv6_cidr_to_range(to_ipv6('2001:db8:1::1'), 48) as `range`;
+---------------------------------------------------------------------+
| {"min":"2001:db8:1::", "max":"2001:db8:1:ffff:ffff:ffff:ffff:ffff"} |
+---------------------------------------------------------------------+

The out-of-range example still raises Illegal cidr value '129' as documented.