Add the available devices option to the help #2850

Author: etabakov

docs/man_pages/device/device-android.md

@@ -8,6 +8,7 @@ General | `$ tns device android [--timeout <Milliseconds>]`
 Lists all recognized connected Android physical and running virtual devices with serial number and index. <% if(isHtml) { %>If a connected Android device is not shown in the list, make sure that you have installed the required Android USB drivers on your system and that USB debugging is enabled on the device.<% } %> 
 
 ### Options
+* `--available-devices` - Lists all available emulators for Android.
 * `--timeout` - Sets the time in milliseconds for the operation to search for connected devices before completing. If not set, the default value is 4000. <% if(isHtml) { %>The operation will continue to wait and listen for newly connected devices and will list them after the specified time expires. 
 
 ### Related Commands

docs/man_pages/device/device-ios.md

@@ -11,6 +11,7 @@ Lists all recognized connected iOS devices with serial number and index.
 
 <% if((isConsole && (isWindows || isMacOS)) || isHtml) { %>  
 ### Options
+* `--available-devices` - Lists all available emulators for iOS.
 * `--timeout` - Sets the time in milliseconds for the operation to search for connected devices before completing. If not set, the default value is 4000. <% } %><% if(isHtml) { %>The operation will continue to wait and listen for newly connected devices and will list them after the specified time expires.
 
 ### Command Limitations

docs/man_pages/device/device.md

@@ -20,6 +20,10 @@ Lists all recognized connected Android <% if(isWindows || isMacOS) { %>or iOS de
 
 * You can run `$ tns device ios` on Windows and OS X systems.
 
+### Aliases
+
+* You can use `$ tns devices` as an alias for `$ tns device`. 
+
 ### Related Commands
 
 Command | Description