Amend mailmap for whitequark

Author: Mark-Simulacrum

.mailmap

@@ -204,7 +204,7 @@ Paul Faria <paul_faria@ultimatesoftware.com> Paul Faria <Nashenas88@gmail.com>
 Peer Aramillo Irizar <peer.aramillo.irizar@gmail.com> parir <peer.aramillo.irizar@gmail.com>
 Peter Elmers <peter.elmers@yahoo.com> <peter.elmers@rice.edu>
 Peter Liniker <peter.liniker+github@gmail.com>
-Peter Zotov <whitequark@whitequark.org>
+whitequark <whitequark@whitequark.org>
 Phil Dawes <phil@phildawes.net> Phil Dawes <pdawes@drw.com>
 Philipp Brüschweiler <blei42@gmail.com> <blei42@gmail.com>
 Philipp Brüschweiler <blei42@gmail.com> <bruphili@student.ethz.ch>