How to use devices: better cross-referencing

A lot of options of ``qvm-device`` command have been converted to Sphinx
options directives and references.

The `action-1` role doesn't seem to be used and the duplicate title was
producing a warning.

The Qubes Device Widget tray icon is presented as a figure, to get a
more consitent paragraph.

SYNOPSIS have been changed to code blocks.

The Device Widget icon is updated (from
(qubes-desktop-linux-manager)[QubesOS/qubes-desktop-linux-manager/tree/release4.2/].
As the original PNG was deleted, all the ``how-to-use-*-devices`` have
been updated too.
QubesOS/qubes-issues#4692 is closed so the corresponding paragraph has
been removed.

user/how-to-guides/how-to-use-block-storage-devices.rst

@@ -15,7 +15,13 @@ Using the Devices Widget to Attach a Drive
 
 Qubes OS supports the ability to attach a USB drive (or just its partitions) to any qube easily, no matter which qube handles the USB controller.
 
-Attaching USB drives is integrated into the Devices Widget: |device manager icon| Simply insert your USB drive and click on the widget. You will see multiple entries for your USB drive; typically, ``sys-usb:sda``, ``sys-usb:sda1``, and ``sys-usb:2-1`` for example. Entries starting with a number (e.g. here ``2-1``) are the :doc:`whole usb-device </user/how-to-guides/how-to-use-usb-devices>`. Entries without a number (e.g. here ``sda``) are the whole block-device. Other entries are partitions of that block-device (e.r. here ``sda1``).
+.. figure:: /attachment/doc/qubes-devices.svg
+   :alt:
+   :align: center
+
+   Qubes Devices Widget tray icon 
+
+Attaching USB drives is integrated into the Devices Widget. Simply insert your USB drive and click on the widget. You will see multiple entries for your USB drive; typically, ``sys-usb:sda``, ``sys-usb:sda1``, and ``sys-usb:2-1`` for example. Entries starting with a number (e.g. here ``2-1``) are the :doc:`whole usb-device </user/how-to-guides/how-to-use-usb-devices>`. Entries without a number (e.g. here ``sda``) are the whole block-device. Other entries are partitions of that block-device (e.r. here ``sda1``).
 
 The simplest option is to attach the entire block drive. In our example, this is ``sys-usb:sda``, so hover over it. This will pop up a submenu showing running VMs to which the USB drive can be connected. Click on one and your USB drive will be attached!
 
@@ -47,7 +53,7 @@ Command Line Tool Guide
 -----------------------
 
 
-The command-line tool you may use to mount whole USB drives or their partitions is ``qvm-block``, a shortcut for ``qvm-device block``.
+The command-line tool you may use to mount whole USB drives or their partitions is ``qvm-block``, a shortcut for :option:`qvm-device block`.
 
 ``qvm-block`` won’t recognise your device by any given name, but rather the device-node the sourceVM assigns. So make sure you have the drive available in the sourceVM, then list the available block devices (step 1.) to find the corresponding device-node.
 
@@ -182,7 +188,7 @@ To attach a file as block device to another qube, first turn it into a loopback
 
    `This command <https://linux.die.net/man/8/losetup>`__ will create the device node ``/dev/loop0`` or, if that is already in use, increase the trailing integer until that name is still available. Afterwards it prints the device-node-name it found.
 
-2. If you want to use the GUI, you’re done. Click the Device Manager |device manager icon| and select the ``loop0``-device to attach it to another qube.
+2. If you want to use the GUI, you’re done. Click the Device Widget and select the ``loop0``-device to attach it to another qube.
 
    - If you rather use the command line, continue:
 
@@ -278,5 +284,3 @@ usage example:
 
 
 This option accepts ``cdrom`` and ``disk``, default is ``disk``.
-
-.. |device manager icon| image:: /attachment/doc/media-removable.png