Reuse gitsigns information

templates/nvim/lua/lua-line.lua.j2

@@ -13,10 +13,26 @@ local function active_lsps()
   return ('LSP: %s (%d)'):format(preview_client.name, #attached_clients)
 end
 
+local function diff_source()
+  local gitsigns = vim.b.gitsigns_status_dict
+  if gitsigns then
+    return {
+      added = gitsigns.added,
+      modified = gitsigns.changed,
+      removed = gitsigns.removed
+    }
+  end
+end
+
 lualine.setup {
   sections = {
     lualine_a = {'mode'},
-    lualine_b = {'branch', 'diff', 'diagnostics', active_lsps },
+    lualine_b = {
+      {'b:gitsigns_head', icon = ''},
+      {'diff', source = diff_source},
+      'diagnostics',
+      active_lsps
+    },
     lualine_c = {
       {
         'filename',