Revert changes to bootstrapping, make checkhealth produce more meaningful message.

README.md

@@ -39,11 +39,14 @@ You can add the following Lua code to your `init.lua` to bootstrap **lazy.nvim**
 ```lua
 local lazypath = vim.fn.stdpath("data") .. "/lazy/lazy.nvim"
 if not vim.loop.fs_stat(lazypath) then
-  vim.fn.system({ "git", "clone",
-    "--filter=blob:none", "--depth=1",
+  vim.fn.system({
+    "git",
+    "clone",
+    "--filter=blob:none",
     "https://github.com/folke/lazy.nvim.git",
-    lazypath })
-  vim.fn.system({ "git", "-C", lazypath, "checkout", "tags/stable" }) -- last stable release
+    "--branch=stable", -- latest stable release
+    lazypath,
+  })
 end
 vim.opt.rtp:prepend(lazypath)
 ```