vim-patch:9.1.1504: filetype: numbat files are not recognized

Problem:  filetype: numbat files are not recognized
Solution: detect *.nbt files as numbat filetype (0xadk)

References:
- https://github.com/sharkdp/numbat
- https://github.com/sharkdp/numbat/tree/master/numbat/modules

closes: vim/vim#17643

20eb68a8f2

Co-authored-by: 0xadk <0xadk@users.noreply.github.com>

runtime/lua/vim/filetype.lua

@@ -871,6 +871,7 @@ local extension = {
   nsh = 'nsis',
   nt = 'ntriples',
   nu = 'nu',
+  nbt = 'numbat',
   obj = 'obj',
   objdump = 'objdump',
   cppobjdump = 'objdump',