refactor: moved handler to separate modules

lua/lazy/core/handler/cmd.lua

@@ -0,0 +1,45 @@
+local Util = require("lazy.core.util")
+local Loader = require("lazy.core.loader")
+
+---@class LazyCmdHandler:LazyHandler
+local M = {}
+
+local function _load(plugin, cmd)
+  vim.api.nvim_del_user_command(cmd)
+  Util.track({ cmd = cmd })
+  Loader.load(plugin, { cmd = cmd })
+  Util.track()
+end
+
+---@param plugin LazyPlugin
+---@param cmd string
+function M:_add(plugin, cmd)
+  vim.api.nvim_create_user_command(cmd, function(event)
+    _load(plugin, cmd)
+    vim.cmd(
+      ("%s %s%s%s %s"):format(
+        event.mods or "",
+        event.line1 == event.line2 and "" or event.line1 .. "," .. event.line2,
+        cmd,
+        event.bang and "!" or "",
+        event.args or ""
+      )
+    )
+  end, {
+    bang = true,
+    nargs = "*",
+    complete = function()
+      _load(plugin, cmd)
+      -- HACK: trick Neovim to show the newly loaded command completion
+      vim.api.nvim_input("<space><bs><tab>")
+    end,
+  })
+end
+
+---@param _plugin LazyPlugin
+---@param value string
+function M:_del(_plugin, value)
+  pcall(vim.api.nvim_del_user_command, value)
+end
+
+return M