Remove Backspace key for file deletion

Solution still needed for Mac, which doesn't have a Delete key on the
keyboard.

cmd/diskgem/dguiabout.go

@@ -37,7 +37,7 @@ func uiAbout(ui *gocui.Gui, v *gocui.View) error {
 		  - Arrow keys to navigate.
 		  - Tab to switch between panes.
 		  - Enter to upload/download files.
-		  - Backspace to delete files.
+		  - Delete to delete files.
 	`
 	fmt.Fprintln(view, strings.Join([]string{
 		"\n\n\n", aboutText, "\n  DiskGem ",

cmd/diskgem/dguikeys.go

@@ -42,8 +42,6 @@ func uiKeysBind(ui *gocui.Gui) error {
 	ui.SetKeybinding("", gocui.KeyTab, gocui.ModNone, uiKeysTab)
 	ui.SetKeybinding("", gocui.KeyEnter, gocui.ModNone, uiKeysEnter)
 	ui.SetKeybinding("", gocui.KeyDelete, gocui.ModNone, uiKeysDelete)
-	ui.SetKeybinding("", gocui.KeyBackspace, gocui.ModNone, uiKeysDelete)
-	ui.SetKeybinding("", gocui.KeyBackspace2, gocui.ModNone, uiKeysDelete)
 	ui.SetKeybinding("", gocui.KeyArrowUp, gocui.ModNone, uiKeysArrowUp)
 	ui.SetKeybinding("", gocui.KeyArrowDown, gocui.ModNone, uiKeysArrowDown)
 	ui.SetKeybinding("", gocui.KeyArrowLeft, gocui.ModNone, uiKeysArrowLeft)

docs/man/diskgem.1

@@ -28,7 +28,7 @@ Tab is used for switching between the left pane (local files) and the right pane
 .IP \(bu
 Enter is used for uploading or downloading files. Multiple parallel transfers are supported.
 .IP \(bu
-Backspace is used for deleting files.
+Delete is used for deleting files.
 .P
 Some windows offering extended features are also accessible via certain key combinations:
 .IP \(bu