Probably typo in multixact.c

Hi

In multixact.c I found some comments like the following:

*        Similar to AtEOX_MultiXact but for COMMIT PREPARED
* Discard the local MultiXactId cache like in AtEOX_MultiXact

Since there's no function called "AtEOX_MultiXact" in the code,
I think the "AtEOX_MultiXact" may be a typo.

AtEOXact_MultiXact seems to be the right function here.

Best regards,
houzj