minor typo in playbooks_variables.rst

so so, this should probably be fixed!

docsite/rst/playbooks_variables.rst

@@ -43,7 +43,7 @@ Easy enough, let's move on.
 Variables Defined in Inventory
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-We've actually already covered a lot about variables in another section, so so far this shouldn't be terribly new, but
+We've actually already covered a lot about variables in another section, so far this shouldn't be terribly new, but
 a bit of a refresher.
 
 Often you'll want to set variables based on what groups a machine is in.  For instance, maybe machines in Boston