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/finders/async_job_finder.lua

@@ -50,6 +50,7 @@ return function(opts)
       command = job_opts.command,
       args = job_opts.args,
       cwd = job_opts.cwd or opts.cwd,
+      env = job_opts.env or opts.env,
       writer = writer,
 
       stdout = stdout,

lua/telescope/finders/async_oneshot_finder.lua

@@ -11,6 +11,7 @@ return function(opts)
 
   local entry_maker = opts.entry_maker or make_entry.gen_from_string
   local cwd = opts.cwd
+  local env = opts.env
   local fn_command = assert(opts.fn_command, "Must pass `fn_command`")
 
   local results = vim.F.if_nil(opts.results, {})
@@ -47,6 +48,7 @@ return function(opts)
           command = job_opts.command,
           args = job_opts.args,
           cwd = cwd,
+          env = env,
 
           stdout = stdout,
         }