Fix RFC3339 typo in docs

Signed-off-by: Iain MacDonald <ijmacd@gmail.com>

Author: IJMacD

docs/reference/commandline/system_prune.md

@@ -107,7 +107,7 @@ The `until` filter can be Unix timestamps, date formatted
 timestamps, or Go duration strings (e.g. `10m`, `1h30m`) computed
 relative to the daemon machine’s time. Supported formats for date
 formatted time stamps include RFC3339Nano, RFC3339, `2006-01-02T15:04:05`,
-`2006-01-02T15:04:05.999999999`, `2006-01-02Z07:00`, and `2006-01-02`. The local
+`2006-01-02T15:04:05.999999999`, `2006-01-02T07:00`, and `2006-01-02`. The local
 timezone on the daemon will be used if you do not provide either a `Z` or a
 `+-00:00` timezone offset at the end of the timestamp.  When providing Unix
 timestamps enter seconds[.nanoseconds], where seconds is the number of seconds

man/src/container/logs.md

@@ -14,7 +14,7 @@ The `--since` and `--until` options can be Unix timestamps, date formatted times
 or Go duration strings (e.g. `10m`, `1h30m`) computed relative to the client machine's
 time. Supported formats for date formatted time stamps include RFC3339Nano,
 RFC3339, `2006-01-02T15:04:05`, `2006-01-02T15:04:05.999999999`,
-`2006-01-02Z07:00`, and `2006-01-02`. The local timezone on the client will be
+`2006-01-02T07:00`, and `2006-01-02`. The local timezone on the client will be
 used if you do not provide either a `Z` or a `+-00:00` timezone offset at the
 end of the timestamp.  When providing Unix timestamps enter
 seconds[.nanoseconds], where seconds is the number of seconds that have elapsed
@@ -37,4 +37,4 @@ $ docker logs -f --until=2s test
 Tue 14 Nov 2017 16:40:00 CET
 Tue 14 Nov 2017 16:40:01 CET
 Tue 14 Nov 2017 16:40:02 CET
-```
+```