.mailmap: Document file format.

Note that official file format documentation is in git-shortlog(1), but
provide a simple quick reference for the two types of entries currently
used in this file.

A third type of entry was used previously, but this commit simplifies
them into one of the two forms documented.

Signed-off-by: Russell Bryant <[email protected]>
Acked-by: Simon Horman <[email protected]>

.mailmap

@@ -1,13 +1,24 @@
+# See git-shortlog(1) for official documentation of this file format.
+#
+# Name <email>
+#   Use "Name" for any commit with address "<email>".  This is useful when a person
+#   has commits using different spellings of their name, but with the same email
+#   address.
+#
+# Name <email> <email2>
+#   Use "Name" and "<email>" for any commit with the address "<email2>".  This is useful
+#   when a person has used more than one email address.
+
 Aaron Conole <[email protected]> <[email protected]>
 Aaron Conole <[email protected]> <[email protected]>
 Aaron Rosen <[email protected]> <[email protected]>
 Alex Wang <[email protected]> <[email protected]>
 Alexey I. Froloff <[email protected]> <[email protected]>
+Alin Serdean <[email protected]>
 Alin Serdean <[email protected]> <aserdean at cloudbasesolutions.com>
-Alin Serdean <[email protected]> Alin Gabriel Sardean <[email protected]>
+Andy Zhou <[email protected]>
 Andy Zhou <[email protected]> <[email protected]>
 Andy Zhou <[email protected]> <[email protected]>
-Andy Zhou <[email protected]> andy zhou <[email protected]>
 Ansis Atteka <[email protected]> <[email protected]>
 Ansis Atteka <[email protected]> <[email protected]>
 Anupam Chanda <[email protected]> <[email protected]>
@@ -25,8 +36,8 @@ Fischetti, Antonio <[email protected]>
 Flavio Fernandes <[email protected]>
 Flavio Leitner <[email protected]> <[email protected]>
 Gal Sagie <[email protected]>
+Gurucharan Shetty <[email protected]>
 Gurucharan Shetty <[email protected]> <[email protected]>
-Gurucharan Shetty <[email protected]> Guru Shetty <[email protected]>
 Henry Mai <[email protected]> <[email protected]>
 Hui Kang <[email protected]> <[email protected]>
 Ian Campbell <[email protected]> <[email protected]>
@@ -51,7 +62,7 @@ Raju Subramanian <[email protected]>
 Ralf Spenneberg <[email protected]>
 Rami Rosen <[email protected]>
 Ramu Ramamurthy <[email protected]> <[email protected]>
-Robert Åkerblom-Andersson <[email protected]> Robert Åkerblom-Andersson <[email protected]>
+Robert Åkerblom-Andersson <[email protected]> <[email protected]>
 Romain Lenglet <[email protected]> <[email protected]>
 Romain Lenglet <[email protected]> <[email protected]>
 Russell Bryant <[email protected]> <[email protected]>