perldelta: Fix typo

Spotted by Lukas Mai

Author: khwilliamson

pod/perldelta.pod

@@ -352,7 +352,7 @@ C<qr/(?[ () ])/> no longer segfaults, giving a syntax error message instead.
 
 =item *
 
-Regular expression possesive quantifier v5.20 regression now fixed.
+Regular expression possessive quantifier v5.20 regression now fixed.
 C<qr/>I<PAT>C<{>I<min>,I<max>C<}+>C</> is supposed to behave identically
 to C<qr/(?E<gt>>I<PAT>C<{>I<min>,I<max>C<})/>.  Since v5.20, this didn't
 work if I<min> and I<max> were equal.  [perl #125825]