Update documentation

Author: fredizzimo

website/docs/configuration.md

@@ -1234,3 +1234,30 @@ Only for the `railgun` vfx mode.
 
 Sets the velocity rotation speed of particles. The higher, the less particles actually move and look
 more "nervous", the lower, the more it looks like a collapsing sine wave.
+
+### Automatic settings, should be turned on/off for debug purposes only
+
+Note: These settings will be removed when the features are deemed stable. In most cases they are
+only here because the automatic detection of Neovim nightly versions does not always work.
+
+#### Autodetect mouse grid
+
+VimScript:
+
+```vim
+let g:neovide_has_mouse_grid_detection = v:true
+```
+
+Lua:
+
+```lua
+vim.g.neovide_has_mouse_grid_detection = true
+```
+
+**Unreleased yet.**
+
+**Requires Neovim 0.12.0.**
+
+Neovim will detect the mouse grid for much better mouse compatibility when enabled. This is
+automaticaly enabled starting from Neovim Nightly September 20. 2025. You should not try to enable
+it manually for unsupported versions, since the behaviour is undefined.