Make legacy/alias properties non-enumerable: computer, modem

I noticed these redundant properties were being logged for every logon in
logon.jsonl. We don't need these properties separately enumerable, and really
they shouldn't be used anyway.

computer is an alias of host_name
modem is an alias of connection

src/sbbs3/js_user.c

@@ -809,7 +809,7 @@ static jsSyncPropertySpec js_user_properties[] = {
 	{	"note"				,USER_PROP_NOTE		 	,USER_PROP_FLAGS,		310},
 	{	"ip_address"		,USER_PROP_IPADDR	 	,USER_PROP_FLAGS,		310},
 	{	"host_name"			,USER_PROP_COMP		 	,USER_PROP_FLAGS,		310},
-	{	"computer"			,USER_PROP_COMP		 	,USER_PROP_FLAGS,		310},
+	{	"computer"			,USER_PROP_COMP		 	,0, /* Alias */			310},
 	{	"comment"			,USER_PROP_COMMENT	 	,USER_PROP_FLAGS,		310},
 	{	"netmail"			,USER_PROP_NETMAIL	 	,USER_PROP_FLAGS,		310},
 	{	"email"				,USER_PROP_EMAIL	 	,USER_PROP_FLAGS|JSPROP_READONLY,		310},
@@ -823,7 +823,7 @@ static jsSyncPropertySpec js_user_properties[] = {
 	{	"birthday"			,USER_PROP_BIRTHDAY  	,USER_PROP_FLAGS,		31802},
 	{	"age"				,USER_PROP_AGE			,USER_PROP_FLAGS|JSPROP_READONLY,		310},
 	{	"connection"		,USER_PROP_MODEM      	,USER_PROP_FLAGS,		310},
-	{	"modem"				,USER_PROP_MODEM      	,USER_PROP_FLAGS,		310},
+	{	"modem"				,USER_PROP_MODEM      	,0, /* Alias */			310},
 	{	"screen_rows"		,USER_PROP_ROWS		 	,USER_PROP_FLAGS,		310},
 	{	"screen_columns"	,USER_PROP_COLS		 	,USER_PROP_FLAGS,		31802},
 	{	"gender"			,USER_PROP_SEX		 	,USER_PROP_FLAGS,		310},
@@ -855,9 +855,8 @@ static const char* user_prop_desc[] = {
 	,"Chat handle"
 	,"Language code (blank, if default, e.g. English)"
 	,"Sysop note"
-	,"IP address last logged on from"
-	,"Host name last logged on from"
-	,"AKA host_name"
+	,"IP address last logged-in from"
+	,"Host name last logged-in from (AKA <tt>computer</tt>)"
 	,"Sysop's comment"
 	,"External e-mail address"
 	,"Local Internet e-mail address	- <small>READ ONLY</small>"
@@ -870,8 +869,7 @@ static const char* user_prop_desc[] = {
 	,"Birth month (1-12)"
 	,"Birth day of month (1-31)"
 	,"Calculated age in years - <small>READ ONLY</small>"
-	,"Connection type (protocol)"
-	,"AKA connection"
+	,"Connection type (protocol, AKA <tt>modem</tt>)"
 	,"Terminal rows (0 = auto-detect)"
 	,"Terminal columns (0 = auto-detect)"
 	,"Gender type (e.g. M or F or any single-character)"