plugins: replace zen-mode by true-zen

- Removes the distraction-free plugin zen-mode, as it has some weird
  performance issue.
- Adds the true-zen distraction-free plugin which seems better in some
  ways.

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

lua/custom/plugins/true-zen.lua

@@ -0,0 +1,28 @@
+local api = vim.api
+
+api.nvim_set_keymap("n", "<leader>zn", ":TZNarrow<CR>", {})
+api.nvim_set_keymap("v", "<leader>zn", ":'<,'>TZNarrow<CR>", {})
+api.nvim_set_keymap("n", "<leader>zf", ":TZFocus<CR>", {})
+api.nvim_set_keymap("n", "<leader>zm", ":TZMinimalist<CR>", {})
+api.nvim_set_keymap("n", "<leader>za", ":TZAtaraxis<CR>", {})
+
+return {
+  "Pocco81/true-zen.nvim",
+  -- Twilight allows to dim text outside of the cursor line.
+  dependencies = {
+    "folke/twilight.nvim",
+    opts = {
+      -- Set the context to null in order to avoid highlighting to much
+      -- paragraphs in markdown.
+      context = 0,
+    },
+  },
+  config = function ()
+    require('true-zen').setup({
+    integrations = {
+      twilight = true,
+      lualine = true
+    }
+  })
+  end
+}

lua/custom/plugins/zen-mode.lua

@@ -1,42 +0,0 @@
---  Zen mode with twilight.
---    Improves the edition experience with distraction free feature.
-
-return {
-  "folke/zen-mode.nvim",
-  ft = {
-    "markdown",
-    "pandoc"
-  },
-  -- Twilight allows to dim text outside of the cursor line.
-  dependencies = {
-    "folke/twilight.nvim",
-    opts = {
-      -- Set the context to null in order to avoid highlighting to much
-      -- paragraphs in markdown.
-      context = 0,
-    },
-  },
-  opts = {
-    window = {
-      backdrop = 1,
-      -- Set the window width (85 columns) and height (80%).
-      width = 85,
-      height = .8,
-      options = {
-        -- Disable line numbering, signcolumn and colorcolumn.
-        number = false,
-        signcolumn = "no",
-        colorcolumn = "0"
-      },
-    },
-    plugins = {
-      options = {
-        enabled = true,
-        ruler = false,
-        showcmd = false,
-        foldcolumn = "0"
-      },
-      gitsigns = { enabled = false },
-    },
-  },
-}