patch 9.0.1539: typst filetype is not recognized

Problem:    Typst filetype is not recognized.
Solution:   Distinguish between sql and typst. (Gaetan Lepage, closes #12363)

src/testdir/test_filetype.vim

@@ -564,7 +564,7 @@ let s:filename_checks = {
     \ 'spice': ['file.sp', 'file.spice'],
     \ 'spup': ['file.speedup', 'file.spdata', 'file.spd'],
     \ 'spyce': ['file.spy', 'file.spi'],
-    \ 'sql': ['file.tyb', 'file.typ', 'file.tyc', 'file.pkb', 'file.pks'],
+    \ 'sql': ['file.tyb', 'file.tyc', 'file.pkb', 'file.pks'],
     \ 'sqlj': ['file.sqlj'],
     \ 'prql': ['file.prql'],
     \ 'sqr': ['file.sqr', 'file.sqi'],
@@ -2047,4 +2047,35 @@ func Test_lsl_file()
   filetype off
 endfunc
 
+func Test_typ_file()
+  filetype on
+
+  " SQL type file
+
+  call writefile(['CASE = LOWER'], 'Xfile.typ', 'D')
+  split Xfile.typ
+  call assert_equal('sql', &filetype)
+  bwipe!
+
+  call writefile(['TYPE foo'], 'Xfile.typ')
+  split Xfile.typ
+  call assert_equal('sql', &filetype)
+  bwipe!
+
+  " typst document
+
+  call writefile(['this is a fallback'], 'Xfile.typ')
+  split Xfile.typ
+  call assert_equal('typst', &filetype)
+  bwipe!
+
+  let g:filetype_typ = 'typst'
+  split test.typ
+  call assert_equal('typst', &filetype)
+  bwipe!
+  unlet g:filetype_typ
+
+  filetype off
+endfunc
+
 " vim: shiftwidth=2 sts=2 expandtab

src/version.c

@@ -695,6 +695,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    1539,
 /**/
     1538,
 /**/