zenmode: Improve slightly the configuration

- Disables the foldcolumn which displays the fold level.
- Removes the backdrop to get a better color experience.
- Removes the colorcolumn in zen mode.

Co-Authored-by: iGor milhit <igor@milhit.ch>

lua/custom/plugins/zen-mode.lua

@@ -18,6 +18,7 @@ return {
   },
   opts = {
     window = {
+      backdrop = 1,
       -- Set the window width (85 columns) and height (80%).
       width = 85,
       height = .8,
@@ -25,6 +26,7 @@ return {
         -- Disable line numbering.
         number = false,
         signcolumn = "no",
+        colorcolumn = "0"
       },
     },
     plugins = {
@@ -32,6 +34,7 @@ return {
         enabled = true,
         ruler = false,
         showcmd = false,
+        foldcolumn = "0"
       },
       gitsigns = { enabled = false },
     },