Resolves replace_name and replace_email to real_name and real_email.
If this is NULL, no substitution is performed.
| this |
the mailmap to search for replacements in. |
| real_name |
the real name of the person. |
| real_email |
the real email of the person. |
| replace_name |
the name to replace. |
| replace_email |
the email to replace. |