docs: Correct the release date of 5.2 stable

A table lists the 5.2 stable release date as September 15, but it was
released on July 7. This may confuse a reader who is trying to
understand the stable update release cycle.
Signed-off-by: Billy Wilson <billy_wilson@byu.edu>
Link: https://lore.kernel.org/r/20200806231754.7735-1-billy_wilson@byu.eduSigned-off-by: Jonathan Corbet <corbet@lwn.net>

Documentation/process/2.Process.rst

@@ -113,7 +113,7 @@ than one development cycle past their initial release. So, for example, the
 5.2 kernel's history looked like this (all dates in 2019):
 
 	==============  ===============================
-	September 15 	5.2 stable release
+	July 7		5.2 stable release
 	July 14		5.2.1
 	July 21		5.2.2
 	July 26		5.2.3