fix (#1319): gitsigns deprecated functions

- This commit change two functions that are marked as deprecated now:
`gitsigns.stage_hunk` and `gitsigns.toggle_deleted`

lua/kickstart/plugins/gitsigns.lua

@@ -44,7 +44,7 @@ return {
         map('n', '<leader>hs', gitsigns.stage_hunk, { desc = 'git [s]tage hunk' })
         map('n', '<leader>hr', gitsigns.reset_hunk, { desc = 'git [r]eset hunk' })
         map('n', '<leader>hS', gitsigns.stage_buffer, { desc = 'git [S]tage buffer' })
-        map('n', '<leader>hu', gitsigns.undo_stage_hunk, { desc = 'git [u]ndo stage hunk' })
+        map('n', '<leader>hu', gitsigns.stage_hunk, { desc = 'git [u]ndo stage hunk' })
         map('n', '<leader>hR', gitsigns.reset_buffer, { desc = 'git [R]eset buffer' })
         map('n', '<leader>hp', gitsigns.preview_hunk, { desc = 'git [p]review hunk' })
         map('n', '<leader>hb', gitsigns.blame_line, { desc = 'git [b]lame line' })
@@ -54,7 +54,7 @@ return {
         end, { desc = 'git [D]iff against last commit' })
         -- Toggles
         map('n', '<leader>tb', gitsigns.toggle_current_line_blame, { desc = '[T]oggle git show [b]lame line' })
-        map('n', '<leader>tD', gitsigns.toggle_deleted, { desc = '[T]oggle git show [D]eleted' })
+        map('n', '<leader>tD', gitsigns.preview_hunk_inline, { desc = '[T]oggle git show [D]eleted' })
       end,
     },
   },