docs(readme): add configuration index with plugin links and line references

Author: glaulher

README.md

@@ -150,6 +150,35 @@ examples of adding popularly requested plugins.
     * [Restructure the configuration](https://github.com/nvim-lua/kickstart.nvim/issues/218)
     * [Reorganize init.lua into a multi-file setup](https://github.com/nvim-lua/kickstart.nvim/pull/473)
 
+
+## Configuration
+
+This section provides quick links to the configuration of each plugin.
+
+### Plugins configured in `init.lua`
+
+- [guess-indent.nvim](init.lua#L250)
+- [gitsigns.nvim](init.lua#L275)
+- [which-key.nvim](init.lua#L302)
+- [telescope.nvim](init.lua#L362)
+- [lazydev.nvim](init.lua#L469)
+- [nvim-lspconfig](init.lua#L480)
+- [conform.nvim](init.lua#L762)
+- [blink.cmp](init.lua#L803)
+- [tokyonight.nvim](init.lua#L906)
+- [todo-comments.nvim](init.lua#L924)
+- [mini.nvim](init.lua#L927)
+- [nvim-treesitter](init.lua#L964)
+
+### Plugins with dedicated configuration files
+
+- [autopairs.lua](lua/kickstart/plugins/autopairs.lua)
+- [debug.lua](lua/kickstart/plugins/debug.lua)
+- [gitsigns.lua](lua/kickstart/plugins/gitsigns.lua)
+- [indent_line.lua](lua/kickstart/plugins/indent_line.lua)
+- [lint.lua](lua/kickstart/plugins/lint.lua)
+- [neo-tree.lua](lua/kickstart/plugins/neo-tree.lua)
+
 ### Install Recipes
 
 Below you can find OS specific install instructions for Neovim and dependencies.

init.lua

@@ -628,32 +628,54 @@ require('lazy').setup({
 
       -- Diagnostic Config
       -- See :help vim.diagnostic.Opts
-      vim.diagnostic.config {
-        severity_sort = true,
-        float = { border = 'rounded', source = 'if_many' },
-        underline = { severity = vim.diagnostic.severity.ERROR },
-        signs = vim.g.have_nerd_font and {
-          text = {
-            [vim.diagnostic.severity.ERROR] = '󰅚 ',
-            [vim.diagnostic.severity.WARN] = '󰀪 ',
-            [vim.diagnostic.severity.INFO] = '󰋽 ',
-            [vim.diagnostic.severity.HINT] = '󰌶 ',
-          },
-        } or {},
-        virtual_text = {
-          source = 'if_many',
-          spacing = 2,
-          format = function(diagnostic)
-            local diagnostic_message = {
-              [vim.diagnostic.severity.ERROR] = diagnostic.message,
-              [vim.diagnostic.severity.WARN] = diagnostic.message,
-              [vim.diagnostic.severity.INFO] = diagnostic.message,
-              [vim.diagnostic.severity.HINT] = diagnostic.message,
-            }
-            return diagnostic_message[diagnostic.severity]
-          end,
-        },
-      }
+      -- Diagnostic configuration similar to VS Code's Error Lens.
+      -- In insert mode, diagnostics are displayed as inline virtual text.
+      -- In normal mode, diagnostics are shown as virtual lines below the affected lines.
+
+      local function set_virtual_text(enable)
+        local diagnostic_icons = {
+          [vim.diagnostic.severity.ERROR] = '󰅚 ',
+          [vim.diagnostic.severity.WARN] = '󰀪 ',
+          [vim.diagnostic.severity.INFO] = '󰋽 ',
+          [vim.diagnostic.severity.HINT] = '󰌶 ',
+        }
+
+        vim.diagnostic.config {
+          update_in_insert = true, -- error messages in insert mode
+          severity_sort = true,
+          float = { border = 'rounded', source = 'if_many' },
+          underline = { severity = vim.diagnostic.severity.ERROR },
+          signs = vim.g.have_nerd_font and {
+            text = diagnostic_icons,
+          } or {},
+
+          virtual_lines = not enable and {
+            format = function(diagnostic)
+              return (diagnostic_icons[diagnostic.severity] or '') .. diagnostic.message
+            end,
+          } or false,
+
+          virtual_text = enable and {
+            source = 'if_many',
+            spacing = 2,
+            format = function(diagnostic)
+              return (diagnostic_icons[diagnostic.severity] or '') .. diagnostic.message
+            end,
+          } or false,
+        }
+      end
+
+      vim.api.nvim_create_autocmd('InsertEnter', {
+        callback = function()
+          set_virtual_text(true)
+        end,
+      })
+
+      vim.api.nvim_create_autocmd('InsertLeave', {
+        callback = function()
+          set_virtual_text(false)
+        end,
+      })
 
       -- LSP servers and clients are able to communicate to each other what features they support.
       --  By default, Neovim doesn't support everything that is in the LSP specification.