feat: make buffer previewer default and deprecate bat previewer (#420)

To revert back to bat previewers put this into your config:

file_previewer = require'telescope.previewers'.cat.new,
grep_previewer = require'telescope.previewers'.vimgrep.new,
qflist_previewer = require'telescope.previewers'.qflist.new,

3 files changed, 15 insertions, 13 deletions

diff --git a/README.md b/README.md
index 91ea01b..9ca0da7 100644
--- a/README.md
+++ b/README.md
@@ -160,9 +160,9 @@ require('telescope').setup{
     color_devicons = true,
     use_less = true,
     set_env = { ['COLORTERM'] = 'truecolor' }, -- default = nil,
-    file_previewer = require'telescope.previewers'.cat.new, -- For buffer previewer use `require'telescope.previewers'.vim_buffer_cat.new`
-    grep_previewer = require'telescope.previewers'.vimgrep.new, -- For buffer previewer use `require'telescope.previewers'.vim_buffer_vimgrep.new`
-    qflist_previewer = require'telescope.previewers'.qflist.new, -- For buffer previewer use `require'telescope.previewers'.vim_buffer_qflist.new`
+    file_previewer = require'telescope.previewers'.vim_buffer_cat.new,
+    grep_previewer = require'telescope.previewers'.vim_buffer_vimgrep.new,
+    qflist_previewer = require'telescope.previewers'.vim_buffer_qflist.new,
 
     -- Developer configurations: Not meant for general override
     buffer_previewer_maker = require'telescope.previewers'.buffer_previewer_maker
@@ -424,18 +424,18 @@ Built-in functions. Ready to be bound to any key you like. :smile:
 
 | Previewers                         | Description                                                     |
 |------------------------------------|-----------------------------------------------------------------|
-| `previewers.cat.new`               | Default previewer for files. Uses `cat`/`bat`                   |
-| `previewers.vimgrep.new`           | Default previewer for grep and similar. Uses `cat`/`bat`        |
-| `previewers.qflist.new`            | Default previewer for qflist. Uses `cat`/`bat`                  |
 | `previewers.vim_buffer_cat.new`    | Experimental previewer for files. Uses vim buffers              |
 | `previewers.vim_buffer_vimgrep.new`| Experimental previewer for grep and similar. Uses vim buffers   |
 | `previewers.vim_buffer_qflist.new` | Experimental previewer for qflist. Uses vim buffers             |
+| `previewers.cat.new` (deprecated)  | Default previewer for files. Uses `cat`/`bat`                   |
+| `previewers.vimgrep.new` (deprecated) | Default previewer for grep and similar. Uses `cat`/`bat`     |
+| `previewers.qflist.new` (deprecated) | Default previewer for qflist. Uses `cat`/`bat`                |
 | .................................. | Your next awesome previewer here :D                             |
 
-By default, telescope.nvim uses `cat`/`bat` for preview. However after telescope's new experimental previewers
-are stable this will change. The new experimental previewers use tree-sitter and vim buffers, provide much
-better performance and are ready for daily usage, but there might be cases where it can't detect a Filetype
-correctly, thus leading to wrong highlights. This is because we can't determine the filetype in the traditional way
+The default previewers are from now on `vim_buffer_` previewers. They use vim buffers for displaying files
+and use tree-sitter or regex for file highlighting.
+These previewers are guessing the filetype of the selected file, so there might be cases where it misses,
+thus leading to wrong highlights. This is because we can't determine the filetype in the traditional way
 (we don't do `bufload`. We read the file async with `vim.loop.fs_` and attach only a highlighter), because we can't
 execute autocommands, otherwise the speed of the previewer would slow down considerably.
 If you want to configure more filetypes take a look at
diff --git a/lua/telescope/config.lua b/lua/telescope/config.lua
index 4b13e7a..30526e5 100644
--- a/lua/telescope/config.lua
+++ b/lua/telescope/config.lua
@@ -98,9 +98,9 @@ function config.set_defaults(defaults)
 
   set("file_ignore_patterns", nil)
 
-  set("file_previewer", function(...) return require('telescope.previewers').cat.new(...) end)
-  set("grep_previewer", function(...) return require('telescope.previewers').vimgrep.new(...) end)
-  set("qflist_previewer", function(...) return require('telescope.previewers').qflist.new(...) end)
+  set("file_previewer", function(...) return require('telescope.previewers').vim_buffer_cat.new(...) end)
+  set("grep_previewer", function(...) return require('telescope.previewers').vim_buffer_vimgrep.new(...) end)
+  set("qflist_previewer", function(...) return require('telescope.previewers').vim_buffer_qflist.new(...) end)
   set("buffer_previewer_maker", function(...) return require('telescope.previewers').buffer_previewer_maker(...) end)
 end
 
diff --git a/lua/telescope/previewers/init.lua b/lua/telescope/previewers/init.lua
index b0f49c0..286e483 100644
--- a/lua/telescope/previewers/init.lua
+++ b/lua/telescope/previewers/init.lua
@@ -8,10 +8,12 @@ previewers.new = function(...)
   return Previewer:new(...)
 end
 
+--- Deprecated previewers
 previewers.new_termopen_previewer = term_previewer.new_termopen_previewer
 previewers.cat                    = term_previewer.cat
 previewers.vimgrep                = term_previewer.vimgrep
 previewers.qflist                 = term_previewer.qflist
+---
 
 previewers.new_buffer_previewer   = buffer_previewer.new_buffer_previewer
 previewers.buffer_previewer_maker = buffer_previewer.file_maker