fix #6060: ui: node status: use a clearer label for the root disk usage

The usage of the root file system is shown as '/ HD space'. Users not
familiar with Linux may not read the '/' as the root file system, but
as a separator, which is even less clear with a screen reader.

Label it 'Root Disk usage' instead. This matches the other usage fields
of the panel, like 'RAM usage' and 'SWAP usage', and is the label the
Proxmox Backup Server status uses for the same value, so the string is
already translated in all languages.

Signed-off-by: Michal Fox <me@dualfroz.com>

www/manager6/node/StatusView.js

@@ -70,7 +70,7 @@ Ext.define('PVE.node.StatusView', {
         {
             iconCls: 'fa fa-fw fa-hdd-o',
             itemId: 'rootfs',
-            title: '/ ' + gettext('HD space'),
+            title: gettext('Root Disk usage'),
             valueField: 'rootfs',
             maxField: 'rootfs',
             renderer: Proxmox.Utils.render_node_size_usage,