doc: move mention of log_min_error_statement in a better spot

Previously it was mentioned in the lock_timeout docs in a confusing
location.

Reported-by:  <ivaylo.zlatanov@gmail.com>

Discussion: https://postgr.es/m/157019615723.25307.15449102262106437404@wrigleys.postgresql.org

Backpatch-through: 9.4

doc/src/sgml/config.sgml

@@ -5707,9 +5707,7 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv;
         each lock acquisition attempt.  The limit applies both to explicit
         locking requests (such as <command>LOCK TABLE</>, or <command>SELECT
         FOR UPDATE</> without <literal>NOWAIT</>) and to implicitly-acquired
-        locks.  If <varname>log_min_error_statement</> is set to
-        <literal>ERROR</> or lower, the statement that timed out will be
-        logged.  A value of zero (the default) turns this off.
+        locks.  A value of zero (the default) turns this off.
        </para>
 
        <para>
@@ -5717,7 +5715,9 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv;
         while waiting for locks.  Note that if <varname>statement_timeout</>
         is nonzero, it is rather pointless to set <varname>lock_timeout</> to
         the same or larger value, since the statement timeout would always
-        trigger first.
+        trigger first.  If <varname>log_min_error_statement</> is set to
+        <literal>ERROR</> or lower, the statement that timed out will be
+        logged.
        </para>
 
        <para>