Add mkpasswd as htpasswd generator

Author: tats-u

xml/en/docs/http/ngx_http_auth_basic_module.xml

@@ -96,7 +96,7 @@ The following password types are supported:
 <listitem>
 encrypted with the <c-func>crypt</c-func> function; can be generated using
 the “<command>htpasswd</command>” utility from the Apache HTTP Server
-distribution or the “<command>openssl passwd</command>” command;
+distribution or the “<command>mkpasswd</command>” or “<command>openssl passwd</command>” command;
 </listitem>
 
 <listitem>