Don't fall off the end of perl functions

This complies with the perlcritic policy
Subroutines::RequireFinalReturn, which is a severity 4 policy. Since we
only currently check at severity level 5, the policy is raised to that
level until we move to level 4 or lower, so that any new infringements
will be caught.

A small cosmetic piece of tidying of the pgperlcritic script is
included.

Mike Blackwell

Discussion: https://postgr.es/m/CAESHdJpfFm_9wQnQ3koY3c91FoRQsO-fh02za9R3OEMndOn84A@mail.gmail.com

src/backend/utils/sort/gen_qsort_tuple.pl

@@ -130,6 +130,8 @@ swapfunc(SortTuple *a, SortTuple *b, size_t n)
 #define vecswap(a, b, n) if ((n) > 0) swapfunc(a, b, n)
 
 EOM
+
+	return;
 }
 
 sub emit_qsort_implementation
@@ -263,4 +265,6 @@ loop:
 	}
 }
 EOM
+
+	return;
 }