docs(#3088): split api pre and post, add more comments

Author: alex-courtis

lua/nvim-tree.lua

@@ -795,7 +795,7 @@ function M.setup(conf)
   vim.g.NvimTreeSetup = 1
   vim.api.nvim_exec_autocmds("User", { pattern = "NvimTreeSetup" })
 
-  require("nvim-tree.api-impl").hydrate_after_setup(api)
+  require("nvim-tree.api.impl.post")(api)
 end
 
 vim.g.NvimTreeRequired = 1

lua/nvim-tree/api-impl.lua

@@ -51,6 +51,6 @@ api.tree = require("nvim-tree._meta.api.tree")
 --
 -- Map implementations
 --
-require("nvim-tree.api-impl").hydrate_init(api)
+require("nvim-tree.api.impl.pre")(api)
 
 return api