Update doc/reference/reference_lua/datetime.rst

Co-authored-by: Elena Shebunyaeva <[email protected]>

Author: tmr-g

doc/reference/reference_lua/datetime.rst

@@ -1098,8 +1098,7 @@ that besides the time zone description files also contains a leapseconds file.
 You can use the Lua module :ref:`tarantool <tarantool-module>` to get a used
 version of ``tzdata``.
 
-This section describes how the ``datetime`` module supports leap seconds.
-It's very initially level of support:
+The ``datetime`` module supports leap seconds at the most basic level:
 
 *   The function :ref:`datetime.parse() <datetime-parse>` correctly parses
     an input string with 60 seconds: