Fix timezone docs titles

docs/timezones.rst

@@ -37,20 +37,20 @@ But when passing a timezone to ``.at()``, DST **is** taken into account.
 The job will run at the specified time, even when the clock changes.
 
 Example clock moves forward:
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+~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 A job is scheduled ``.at("02:30", "Europe/Berlin")``.
 When the clock moves from ``02:00`` to ``03:00``, the job will run once at ``03:30``.
 The day after it will return to normal and run at ``02:30``.
 
 Example clock moves backwards:
-~~~~~~~
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 A job is scheduled ``.at("02:30", "Europe/Berlin")``.
 When the clock moves from ``02:00`` to ``03:00``, the job will run once at ``02:30``.
 It will run only at the first time the clock hits ``02:30``, but not the second time.
 The day after, it will return to normal and run at ``02:30``.
 
 Example scheduling across timezones
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+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 Let's say we are in ``Europe/Berlin`` and local datetime is ``2022 march 20, 10:00:00``.
 At this moment daylight saving time is not in effect in Berlin (UTC+1).