docs(iferr): add docs

doc/gopher.nvim.txt

@@ -14,6 +14,7 @@ Table of Contents
   Modifty struct tags................................|gopher.nvim-struct-tags|
   Auto implementation of interface methods..................|gopher.nvim-impl|
   Generating unit tests boilerplate......................|gopher.nvim-gotests|
+  Iferr....................................................|gopher.nvim-iferr|
   Setup `nvim-dap` for Go......................................|gopher.nvim-dap|
 
 ------------------------------------------------------------------------------
@@ -191,6 +192,14 @@ you can do it with:
 if you choose to install `gotests` within neovim, i recommend adding it to your `build` section in your |lazy.nvim|
 
 
+==============================================================================
+------------------------------------------------------------------------------
+                                                             *gopher.nvim-iferr*
+if you're using `iferr` tool, this module provides a way to automatically insert `if err != nil` check.
+Usage ~
+execute `:GoIfErr` near any err variable to insert the check
+
+
 ==============================================================================
 ------------------------------------------------------------------------------
                                                                *gopher.nvim-dap*

lua/gopher/iferr.lua

@@ -1,7 +1,12 @@
+---@toc_entry Iferr
+---@tag gopher.nvim-iferr
+---@text if you're using `iferr` tool, this module provides a way to automatically insert `if err != nil` check.
+---@usage execute `:GoIfErr` near any err variable to insert the check
+
 local c = require "gopher.config"
 local iferr = {}
 
--- That's Lua of vimscript implementation of: github.com/koron/iferr
+-- That's Lua implementation: github.com/koron/iferr
 function iferr.iferr()
   local boff = vim.fn.wordcount().cursor_bytes
   local pos = vim.fn.getcurpos()[2]

scripts/docgen.lua

@@ -13,6 +13,7 @@ local files = {
   "lua/gopher/struct_tags.lua",
   "lua/gopher/impl.lua",
   "lua/gopher/gotests.lua",
+  "lua/gopher/iferr.lua",
   "lua/gopher/dap.lua",
 }