WhatsNew: Start block for 2.0.24

WhatsNew.txt

@@ -1,6 +1,14 @@
 
 This is a list of major changes in SDL's version history.
 
+---------------------------------------------------------------------------
+2.0.24:
+---------------------------------------------------------------------------
+
+General:
+* Added SDL_bsearch() to the stdlib routines
+* Added joystick event SDL_JOYBATTERYUPDATED for when battery status changes.
+
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 2.0.22:
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