feat: All buffer previewers are now async and more config options (#354)

Configure preview window with:
autocmd User TelescopePreviewerLoaded setlocal wrap
autocmd User TelescopePreviewerLoaded setlocal number

file_maker example: Use regex highlighting for certain filetype like `*min.js` because they slow
down things with treesitter highlighter. Just a snippet for tests. We will do an extension :)

local previewers = require('telescope.previewers')
local putils = require('telescope.previewers.utils')
local pfiletype = require('plenary.filetype')

local _bad = { '.*%.min%.js' }
local bad_files = function(filepath)
  for _, v in ipairs(_bad) do
    if filepath:match(v) then
      return true
    end
  end

  return false
end

local new_maker = function(filepath, bufnr, bufname, use_ft_detect, callback)
  if use_ft_detect == nil then use_ft_detect = true end

  if bad_files(filepath) then
    previewers.buffer_previewer_maker(filepath, bufnr, bufname, false, callback)
    local ft = pfiletype.detect(filepath)
    putils.regex_highlighter(bufnr, ft)
  else
    previewers.buffer_previewer_maker(filepath, bufnr, bufname, use_ft_detect, callback)
  end
end

require('telescope').setup {
  defaults = {
    buffer_previewer_maker = new_maker,
  }
}

plugin/telescope.vim

@@ -35,8 +35,10 @@ highlight default link TelescopeResultsStruct Struct
 highlight default link TelescopeResultsVariable SpecialChar
 
 highlight default link TelescopeResultsLineNr LineNr
+highlight default link TelescopeResultsIdentifier Identifier
 highlight default link TelescopeResultsNumber Number
 highlight default link TelescopeResultsComment Comment
+highlight default link TelescopeResultsSpecialComment SpecialComment
 
 " This is like "<C-R>" in your terminal.
 "   To use it, do `cmap <C-R> <Plug>(TelescopeFuzzyCommandSearch)