refactor(gitignore.lua): replace GetProjectRoot function with require statement for

absolute.utils.get-git-root module to improve code organization and readability
feat(gitignore.lua): update keymap description to include GitIgnore prefix for
clarity and consistency with functionality provided by the keymap

lua/absolute/after/gitignore.lua

@@ -1,19 +1,11 @@
 local gitignore = require("gitignore")
-
-function GetProjectRoot()
-    local git_root = vim.fn.systemlist("git rev-parse --show-toplevel")[1]
-    if git_root == nil then
-        return vim.fn.getcwd()
-    else
-        return git_root
-    end
-end
+local GetProjectRoot = require("absolute.utils.get-git-root")
 
 -- Keymaps
 
 local opts = { noremap = true, silent = true }
 
-opts.desc = "Generate .gitignore"
+opts.desc = "GitIgnore: Generate .gitignore"
 
 vim.keymap.set("n", "<leader>gi", function()
     local path = GetProjectRoot()