vim-patch:9.2.0551: filetype: Tolk files are not recognized

Problem:  filetype: Tolk files are not recognized
Solution: Detect *.tolk files as tolk filetype, include a syntax and
          filetype plugin (redavy)

Tolk is a new-generation language for writing smart contracts on TON
blockchain, which is vim/vim#1 in speed among other chains.

Reference:
https://docs.ton.org/blockchain-basics/tolk/overview

closes: vim/vim#20320

b9bba99712

Co-authored-by: redavy <hello.redavy@proton.me>

runtime/ftplugin/tolk.vim

@@ -0,0 +1,22 @@
+" Vim filetype plugin file
+" Language:     Tolk
+" Maintainer:   redavy <hello.redavy@proton.me>
+" Upstream:     https://github.com/redavy/vim-tolk
+" Last Update:  24 May 2026
+
+if exists("b:did_ftplugin")
+  finish
+endif
+let b:did_ftplugin = 1
+
+setlocal commentstring=//\ %s
+
+if get(g:, 'tolk_recommended_style', get(g:, 'recommended_style', 1))
+  setlocal tabstop=2
+  setlocal shiftwidth=2
+  setlocal expandtab
+  setlocal softtabstop=2
+  setlocal cindent
+endif
+
+let b:undo_ftplugin = "setlocal commentstring< tabstop< shiftwidth< expandtab< softtabstop< cindent<"

runtime/lua/vim/filetype.lua

@@ -1350,6 +1350,7 @@ local extension = {
   tiltfile = 'tiltfile',
   tla = 'tla',
   tli = 'tli',
+  tolk = 'tolk',
   toml = 'toml',
   tpp = 'tpp',
   treetop = 'treetop',

runtime/syntax/tolk.vim

@@ -0,0 +1,37 @@
+" Vim syntax file
+" Language:     Tolk
+" Maintainer:   redavy <hello.redavy@proton.me>
+" Upstream:     https://github.com/redavy/vim-tolk
+" Last Update:  28 May 2026
+
+if exists("b:current_syntax")
+  finish
+endif
+
+" Keywords
+syn keyword tolkKeyword  do if as fun asm get try var val lazy
+syn keyword tolkKeyword  else enum true tolk const false throw
+syn keyword tolkKeyword  redef while catch return assert import
+syn keyword tolkKeyword  global repeat contract mutate struct
+syn keyword tolkKeyword  match type null void never
+
+" Strings
+syn region tolkString  start=+"+ end=+"+
+syn region tolkString  start=+'+ end=+'+
+
+" Numbers
+syn match tolkNumber  "\<[0-9]\+\>"
+syn match tolkNumber  "\<0[xX][0-9a-fA-F]\+\>"
+syn match tolkNumber  "\<[0-9]\+\.[0-9]\+\>"
+
+" Comments
+syn match  tolkComment  "//.*$"
+syn region tolkComment  start="/\*" end="\*/"
+
+" Highlights
+hi link tolkKeyword    Keyword
+hi link tolkString     String
+hi link tolkNumber     Number
+hi link tolkComment    Comment
+
+let b:current_syntax = "tolk"

test/old/testdir/test_filetype.vim

@@ -903,6 +903,7 @@ func s:GetFilenameChecks() abort
     \ 'tla': ['file.tla'],
     \ 'tli': ['file.tli'],
     \ 'tmux': ['tmuxfile.conf', '.tmuxfile.conf', '.tmux-file.conf', '.tmux.conf', 'tmux-file.conf', 'tmux.conf', 'tmux.conf.local'],
+    \ 'tolk': ['file.tolk'],
     \ 'toml': ['file.toml', 'uv.lock', 'Gopkg.lock', 'Pipfile', '/home/user/.cargo/config', '.black',
     \          'any/containers/containers.conf', 'any/containers/containers.conf.d/file.conf',
     \          'any/containers/containers.conf.modules/file.conf', 'any/containers/containers.conf.modules/any/file.conf',