feat: add spell checker for both English

the plugin `spellwarn` was added, and set to support
English, the flake was also update to include the new plugin.

Author: iagorrr

flake.lock

@@ -5,7 +5,6 @@
     nixpkgs.url = "github:NixOS/nixpkgs/nixpkgs-unstable";
     flake-utils.url = "github:numtide/flake-utils";
   };
-
   outputs = {
     self,
     nixpkgs,
@@ -208,6 +207,10 @@
       url = "github:folke/snacks.nvim";
       flake = false;
     };
+    "spellwarn.nvim" = {
+      url = "github:ravibrock/spellwarn.nvim";
+      flake = false;
+    };
     "which-key.nvim" = {
       url = "github:folke/which-key.nvim";
       flake = false;

flake.nix

@@ -0,0 +1,54 @@
+--[[
+-- Spell checker plugin set for English
+--
+-- Usage:
+--      ]s            -> jump to next misspelled word
+--      [s            -> jump to previous misspelled word
+--      z=            -> show spelling suggestions
+--      zg            -> add word to dictionary
+--      zw            -> mark word as wrong
+-- ]]
+
+local default_opts = {
+    event = { -- event(s) to refresh diagnostics on
+        "CursorHold",
+        "InsertLeave",
+        "TextChanged",
+        "TextChangedI",
+        "TextChangedP",
+    },
+    enable = true, -- enable diagnostics on startup
+    ft_config = { -- spellcheck method: "cursor", "iter", or boolean
+        alpha = false,
+        help = false,
+        lazy = false,
+        lspinfo = false,
+        mason = false,
+    },
+    ft_default = true, -- default option for unspecified file types
+    max_file_size = nil, -- maximum file size to check in lines (nil for no limit)
+    severity = { -- severity for each spelling error type (false to disable diagnostics for that type)
+        spellbad = "WARN",
+        spellcap = "HINT",
+        spelllocal = "HINT",
+        spellrare = "INFO",
+    },
+    suggest = false, -- show spelling suggestions in diagnostic message (works best with window-style message)
+    num_suggest = 3, -- number of spelling suggestions shown in diagnostic message
+    prefix = "possible misspelling(s): ", -- prefix for each diagnostic message
+    diagnostic_opts = { severity_sort = true }, -- options for diagnostic display
+}
+
+local function config()
+    vim.opt.spell = true
+    vim.opt.spelllang = { "en_us" }
+
+    require("spellwarn").setup(default_opts)
+end
+
+return {
+    "ravibrock/spellwarn.nvim",
+    lazy = false,
+    priority = 1500,
+    config = config,
+}