Revert "improv: use lazy.nvim's recommended bootstrap (better fix for #3

)"

This reverts commit 0d569e5.

Downloading the lazy bootstrap code everytime that nvim is executed
completely breaks neovim if the user is offline or in networks with
resticted internet access. The uncached usage of the bootstrap code
is also not cost-effective.

kickstart-python.lua

@@ -1,5 +1,11 @@
--- BOOTSTRAP LAZY.NVIM https://lazy.folke.io/developers#bootstrap
-load(vim.fn.system("curl -s https://raw.githubusercontent.com/folke/lazy.nvim/main/bootstrap.lua"))()
+-- BOOTSTRAP the plugin manager `lazy.nvim`
+local lazypath = vim.fn.stdpath("data") .. "/lazy/lazy.nvim"
+if not vim.uv.fs_stat(lazypath) then
+	local lazyrepo = "https://github.com/folke/lazy.nvim.git"
+	local out = vim.fn.system({ "git", "clone", "--filter=blob:none", "--branch=stable", lazyrepo, lazypath })
+	if vim.v.shell_error ~= 0 then error("Error cloning lazy.nvim:\n" .. out) end
+end
+vim.opt.runtimepath:prepend(lazypath)
 
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 -- BASIC PYTHON-RELATED OPTIONS