vim-patch:9.1.0591: filetype: *.wl files are not recognized

Problem:  filetype: *.wl files are not recognized
Solution: Detect '*.wl' files as Mathematica package files
          (Jonas Dujava)

closes: vim/vim#15269

c6d7dc0393

Co-authored-by: Jonas Dujava <jonas.dujava@gmail.com>

runtime/lua/vim/filetype.lua

@@ -711,6 +711,7 @@ local extension = {
   mixal = 'mix',
   mm = detect.mm,
   nb = 'mma',
+  wl = 'mma',
   mmp = 'mmp',
   mms = detect.mms,
   DEF = 'modula2',

test/old/testdir/test_filetype.vim

@@ -471,7 +471,7 @@ func s:GetFilenameChecks() abort
     \ 'mgp': ['file.mgp'],
     \ 'mib': ['file.mib', 'file.my'],
     \ 'mix': ['file.mix', 'file.mixal'],
-    \ 'mma': ['file.nb'],
+    \ 'mma': ['file.nb', 'file.wl'],
     \ 'mmp': ['file.mmp'],
     \ 'modconf': ['/etc/modules.conf', '/etc/modules', '/etc/conf.modules', '/etc/modprobe.file', 'any/etc/conf.modules', 'any/etc/modprobe.file', 'any/etc/modules', 'any/etc/modules.conf'],
     \ 'modula3': ['file.m3', 'file.mg', 'file.i3', 'file.ig', 'file.lm3'],