fix: man_pages previewer, respecting MANPATH and apropos output parsing (#1764)

- introducing putils writer and use it rather than using PAGER env var
- introducing env for lua/telescope/_.lua job interface
  - to respect MANPATH (and PATH just in case)
- fix for apropos output parsing might return e.g. `alacritty, Alacritty`
  We need to split on first `,`

lua/telescope/builtin/internal.lua

@@ -663,6 +663,7 @@ internal.man_pages = function(opts)
     return is_darwin and { "apropos", " " } or { "apropos", "" }
   end)
   opts.entry_maker = opts.entry_maker or make_entry.gen_from_apropos(opts)
+  opts.env = { PATH = vim.env.PATH, MANPATH = vim.env.MANPATH }
 
   pickers.new(opts, {
     prompt_title = "Man",