refactor: commands runner (#42)

* feat(utils): first impl of own commands runner

* refactor(gotests): uses own runner instead of vendored

* refactor(utils): back to plenary.job

* refactor(gotests): use new runner, clean code

* fix(runner): now it returns output correctly

* refactor(iferr): use vim.system

i have tried to use _utils.runner, but i can't figure out how to make `< file.go` for the command

* refactor(impl): use new runner

* refactor(installer): use new runner

* refactor(struct_tags): use new runner

* refactor: commands such as :GoGet runs with new runner

* refactor: throw errors in more lua way, i think

* refactor(utils): notify now has title

* refactor: use more correct way of notifying

* refactor(runner): write error message on error

lua/gopher/iferr.lua

@@ -1,22 +1,16 @@
 local c = require("gopher.config").commands
-local u = require "gopher._utils"
 local iferr = {}
 
 -- That's Lua of vimscript implementation of: github.com/koron/iferr
-iferr.iferr = function()
+function iferr.iferr()
   local boff = vim.fn.wordcount().cursor_bytes
-  local cmd = (c.iferr .. " -pos " .. boff)
-  local data = vim.fn.systemlist(cmd, vim.fn.bufnr "%")
+  local pos = vim.fn.getcurpos()[2]
 
+  local data = vim.fn.systemlist((c.iferr .. " -pos " .. boff), vim.fn.bufnr "%")
   if vim.v.shell_error ~= 0 then
-    u.deferred_notify(
-      "command " .. cmd .. " exited with code " .. vim.v.shell_error,
-      vim.log.levels.ERROR
-    )
-    return
+    error("iferr failed: " .. data)
   end
 
-  local pos = vim.fn.getcurpos()[2]
   vim.fn.append(pos, data)
   vim.cmd [[silent normal! j=2j]]
   vim.fn.setpos(".", pos)