docs(docs): update Noctalia external and floating keybinding documentation

docs/desktop/umbriel.mdx

@@ -153,7 +153,7 @@ Noctalia's bar, panels, notifications, dock, OSD, and desktop widgets get blur t
 | `Mod+Shift+F` | maximize to the output edges |
 | `Mod+Ctrl+F` | fullscreen |
 | `Mod+C` | center column |
-| `Mod+Ctrl+O` | toggle floating |
+| `Mod+T` | toggle floating |
 | `Mod+W` | toggle the workspace between the scrolling and dwindle layouts |
 | `Mod+G` | tab the focused window with the windows stacked in its column, or stack a tab group again (scrolling layout; dwindle has no columns). Windows join a group by dragging onto its tab bar |
 | `Mod+Q` | close window |