Initial pgindent run for v12.

This is still using the 2.0 version of pg_bsd_indent.
I thought it would be good to commit this separately,
so as to document the differences between 2.0 and 2.1 behavior.

Discussion: https://postgr.es/m/16296.1558103386@sss.pgh.pa.us

src/backend/utils/hash/hashfn.c

@@ -653,6 +653,7 @@ hash_uint32_extended(uint32 k, uint64 seed)
 	/* report the result */
 	PG_RETURN_UINT64(((uint64) b << 32) | c);
 }
+
 /*
  * string_hash: hash function for keys that are NUL-terminated strings.
  *