Document the possible values for -z.

babeld.man

@@ -52,13 +52,22 @@ functionality is experimental, don't use it unless you know what you are
 doing.
 .TP
 .BI \-z " kind" , factor
-Enable diversity-sensitive routing.  The algorithm used is defined by
-.BR kind ,
-the values of which are currently undocumented.  The value
+Enable diversity-sensitive routing.  The value
+.B kind
+defines the diversity algorithm used, and can be one of
+.B 0
+(no diversity),
+.B 1
+(per-interface diversity with no memory),
+.B 2
+(per-channel diversity with no memory),
+or
+.B 3
+(per-channel diversity with memory).
+The value
 .B factor
 specifies by how much the cost of non-interfering routes is multiplied; the
-default is 0.5.  This option is experimental and subject to change, don't
-use it unless you understand what you are doing.
+default is 0.5.
 .TP
 .BI \-k " priority"
 Specify the priority value used when installing routes into the kernel.