doc: case sensitive rename is not possible on macOS with case insensitive file systems

Author: alex-courtis

doc/nvim-tree-lua.txt

@@ -1800,6 +1800,8 @@ vim.keymap.set("n", "<leader>ms", require("nvim-tree.api").marks.navigate.select
 
 macOS
 - Trash is unavailable
+- Rename to different case is not possible when using a case insensitive file
+  system.
 
 Windows WSL and PowerShell
 - Trash is unavailable