fix(previewer): improve binary mime type check (#3083)

* fix(previewer): improve binary mime type check

Problem: mime type for a ts/js file can either return `text/plain` or
`application/javascript` based on the contents of the file.
Previously, this meant `application/javascript` would be considered
"possibly binary". This, in conjunction with how `vim.filetype.match`
does not give a result for a filename that ends in `.ts`, would lead to
a typescript file taking the path of `check_mime_type` and eventually
`mime_hook`.

Solution: Include `application/javascript` as a non-binary file type
during mime type check.

* [docgen] Update doc/telescope.txt
skip-checks: true

---------

Co-authored-by: Github Actions <actions@github>

lua/telescope/previewers/term_previewer.lua

@@ -3,6 +3,7 @@ local utils = require "telescope.utils"
 local Path = require "plenary.path"
 local from_entry = require "telescope.from_entry"
 local Previewer = require "telescope.previewers.previewer"
+local putil = require "telescope.previewers.utils"
 
 local defaulter = utils.make_default_callable
 
@@ -65,9 +66,8 @@ local cat_maker = function(filename, _, start, _)
   end
 
   if 1 == vim.fn.executable "file" then
-    local output = utils.get_os_command_output { "file", "--mime-type", "-b", filename }
-    local mime_type = vim.split(output[1], "/")[1]
-    if mime_type ~= "text" then
+    local mime_type = utils.get_os_command_output({ "file", "--mime-type", "-b", filename })[1]
+    if putil.binary_mime_type(mime_type) then
       return { "echo", "Binary file found. These files cannot be displayed!" }
     end
   end