vim-patch:8.2.2085: Qt translation file is recognized as typescript

Problem:    Qt translation file is recognized as typescript.
Solution:   Check the first line for "<?xml". (closes vim/vim#7418)
c0d670ce16

runtime/filetype.vim

@@ -1768,8 +1768,13 @@ au BufNewFile,BufReadPost *.tutor		setf tutor
 " TWIG files
 au BufNewFile,BufReadPost *.twig		setf twig
 
-" Typescript
-au BufNewFile,BufReadPost *.ts			setf typescript
+" Typescript or Qt translation file (which is XML)
+au BufNewFile,BufReadPost *.ts
+	\ if getline(1) =~ '<?xml' |
+	\   setf xml |
+	\ else |
+	\   setf typescript |
+	\ endif
 
 " TypeScript with React
 au BufNewFile,BufRead *.tsx			setf typescriptreact

src/nvim/testdir/test_filetype.vim

@@ -471,7 +471,6 @@ let s:filename_checks = {
     \ 'tssgm': ['file.tssgm'],
     \ 'tssop': ['file.tssop'],
     \ 'twig': ['file.twig'],
-    \ 'typescript': ['file.ts'],
     \ 'typescriptreact': ['file.tsx'],
     \ 'uc': ['file.uc'],
     \ 'udevconf': ['/etc/udev/udev.conf'],
@@ -668,5 +667,22 @@ func Test_hook_file()
   filetype off
 endfunc
 
+func Test_ts_file()
+  filetype on
+
+  call writefile(['<?xml version="1.0" encoding="utf-8"?>'], 'Xfile.ts')
+  split Xfile.ts
+  call assert_equal('xml', &filetype)
+  bwipe!
+
+  call writefile(['// looks like Typescript'], 'Xfile.ts')
+  split Xfile.ts
+  call assert_equal('typescript', &filetype)
+  bwipe!
+
+  call delete('Xfile.hook')
+  filetype off
+endfunc
+
 
 " vim: shiftwidth=2 sts=2 expandtab