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 #1 in speed among other chains.

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

closes: #20320

Signed-off-by: redavy <hello.redavy@proton.me>
Signed-off-by: Christian Brabandt <cb@256bit.org>

.github/MAINTAINERS

@@ -339,6 +339,7 @@ runtime/ftplugin/thrift.vim				@jiangyinzuo
 runtime/ftplugin/tiasm.vim				@Freed-Wu
 runtime/ftplugin/tidy.vim				@dkearns
 runtime/ftplugin/tmux.vim				@ericpruitt
+runtime/ftplugin/tolk.vim				@redavy
 runtime/ftplugin/toml.vim				@averms
 runtime/ftplugin/tt2html.vim				@petdance
 runtime/ftplugin/twig.vim				@ribru17
@@ -700,6 +701,7 @@ runtime/syntax/thrift.vim				@jiangyinzuo
 runtime/syntax/tiasm.vim				@Freed-Wu
 runtime/syntax/tidy.vim					@dkearns
 runtime/syntax/tmux.vim					@ericpruitt
+runtime/syntax/tolk.vim					@redavy
 runtime/syntax/toml.vim					@averms
 runtime/syntax/tt2.vim					@petdance
 runtime/syntax/tt2html.vim				@petdance

runtime/autoload/dist/ft.vim

@@ -3,7 +3,7 @@ vim9script
 # Vim functions for file type detection
 #
 # Maintainer:		The Vim Project <https://github.com/vim/vim>
-# Last Change:		2026 May 18
+# Last Change:		2026 May 28
 # Former Maintainer:	Bram Moolenaar <Bram@vim.org>
 
 # These functions are moved here from runtime/filetype.vim to make startup
@@ -2743,6 +2743,8 @@ const ft_from_ext = {
   "sieve": "sieve",
   # TriG
   "trig": "trig",
+  # Tolk
+  "tolk": "tolk",
   # Zig and Zig Object Notation (ZON)
   "zig": "zig",
   "zon": "zig",

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/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"

src/testdir/test_filetype.vim

@@ -904,6 +904,7 @@ def s:GetFilenameChecks(): dict<list<string>>
     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',

src/version.c

@@ -729,6 +729,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    551,
 /**/
     550,
 /**/