runtime(pov): deprecate `#render` and `#statistics` in syntax script

- 3.1g: active
  https://www.povray.org/ftp/pub/povray/Old-Versions/Official-3.1g/Docs/povuser.pdf#page=172
- 3.5 or later: deprecated
  https://www.povray.org/ftp/pub/povray/Old-Versions/Official-3.5/Linux/povlinux.tgz
  ─ povray-3.50c/html/povdoc_172.html
  - https://www.povray.org/documentation/3.7.0/r3_3.html#r3_3_2_7_1

closes: #17177

Signed-off-by: Eisuke Kawashima <e-kwsm@users.noreply.github.com>
Signed-off-by: Christian Brabandt <cb@256bit.org>
diff --git a/runtime/syntax/pov.vim b/runtime/syntax/pov.vim
index 8595bcb..87b2aa5 100644
--- a/runtime/syntax/pov.vim
+++ b/runtime/syntax/pov.vim
@@ -2,7 +2,7 @@
 " Language: PoV-Ray(tm) 3.7 Scene Description Language
 " Maintainer: David Necas (Yeti) <yeti@physics.muni.cz>
 " Last Change: 2011-04-23
-" Required Vim Version: 6.0
+" 2025 Apr 21 by Vim Project (deprecate render and statistics #17177)
 
 " Setup
 " quit when a syntax file was already loaded
@@ -86,7 +86,8 @@
 syn match povIncludeDir "#\s*include\>"
 syn match povFileDir "#\s*\(fclose\|fopen\|read\|write\)\>"
 syn keyword povFileDataType uint8 sint8 unit16be uint16le sint16be sint16le sint32le sint32be
-syn match povMessageDir "#\s*\(debug\|error\|render\|statistics\|warning\)\>"
+syn match povMessageDir "#\s*\(debug\|error\|warning\)\>"
+syn match povMessageDirDeprecated "#\s*\%(render\|statistics\)\>"
 syn region povFileOpen start="#\s*fopen\>" skip=+"[^"]*"+ matchgroup=povOpenType end="\<\(read\|write\|append\)\>" contains=ALLBUT,PovParenError,PovBraceError,@PovPRIVATE transparent keepend
 
 " Literal strings
@@ -126,6 +127,7 @@
 hi def link povFileDir PreProc
 hi def link povFileDataType Special
 hi def link povMessageDir Debug
+hi def link povMessageDirDeprecated povError
 hi def link povAppearance povDescriptors
 hi def link povObjects povDescriptors
 hi def link povGlobalSettings povDescriptors