Add gitsigns essential keymaps

Include essential gitsigns keymaps, for more see gitsigns README:
https://github.com/lewis6991/gitsigns.nvim

init.lua

@@ -255,6 +255,33 @@ require('lazy').setup({
         topdelete = { text = '‾' },
         changedelete = { text = '~' },
       },
+      on_attach = function(bufnr)
+        -- Include essential gitsigns keymaps, for more see gitsigns README:
+        -- https://github.com/lewis6991/gitsigns.nvim
+        local gs = package.loaded.gitsigns
+        local function map(mode, l, r, opts)
+          opts = opts or {}
+          opts.buffer = bufnr
+          vim.keymap.set(mode, l, r, opts)
+        end
+        -- Navigation
+        map({ 'n', 'v' }, ']c', gs.next_hunk, { desc = 'Jump to next git [c]hange' })
+        map({ 'n', 'v' }, '[c', gs.prev_hunk, { desc = 'Jump to previous git [c]hange' })
+        -- Actions
+        map('n', '<leader>hs', gs.stage_hunk, { desc = 'git [s]tage hunk' })
+        map('n', '<leader>hr', gs.reset_hunk, { desc = 'git [r]eset hunk' })
+        map('n', '<leader>hu', gs.undo_stage_hunk, { desc = 'git [u]ndo stage hunk' })
+        map('n', '<leader>hp', gs.preview_hunk, { desc = 'git [p]review hunk' })
+        map('n', '<leader>hb', gs.blame_line, { desc = 'git [b]lame line' })
+        map('n', '<leader>hd', gs.diffthis, { desc = 'git [d]iff against index' })
+        -- Visual mode
+        map('v', '<leader>hs', function()
+          gs.stage_hunk { vim.fn.line '.', vim.fn.line 'v' }
+        end, { desc = 'stage git hunk' })
+        map('v', '<leader>hr', function()
+          gs.reset_hunk { vim.fn.line '.', vim.fn.line 'v' }
+        end, { desc = 'reset git hunk' })
+      end,
     },
   },
 
@@ -287,7 +314,12 @@ require('lazy').setup({
         ['<leader>s'] = { name = '[S]earch', _ = 'which_key_ignore' },
         ['<leader>w'] = { name = '[W]orkspace', _ = 'which_key_ignore' },
         ['<leader>t'] = { name = '[T]oggle', _ = 'which_key_ignore' },
+        ['<leader>h'] = { name = 'Git [H]unk', _ = 'which_key_ignore' },
       }
+      -- visual mode
+      require('which-key').register({
+        ['<leader>h'] = { 'Git [H]unk' },
+      }, { mode = 'v' })
     end,
   },