add Smear defaults

lua/custom/plugins/smear.lua

 return {
   "sphamba/smear-cursor.nvim",
   enabled = true,
-  opts = {},
+  opts = {
+    smear_between_buffers = true,
+    smear_between_neighbor_lines = true,
+    scroll_buffer_space = true,
+    legacy_computing_symbols_support = false,
+  },
 }