runtime(json5): Add TODO support to syntax script (#13743)


Signed-off-by: Danek Duvall <duvall@comfychair.org>
Signed-off-by: Mazunki Hoksaas <rolferen@gmail.com>
Signed-off-by: Christian Brabandt <cb@256bit.org>
diff --git a/runtime/syntax/json5.vim b/runtime/syntax/json5.vim
index 5b01d33..dc0d11b 100644
--- a/runtime/syntax/json5.vim
+++ b/runtime/syntax/json5.vim
@@ -49,9 +49,11 @@
 syn match   json5Key /"\([^"]\|\\"\)\{-}"\ze\s*:/ contains=json5Escape,@Spell
 
 " Comment
-syn region  json5LineComment    start=+\/\/+ end=+$+ keepend contains=@Spell
-syn region  json5LineComment    start=+^\s*\/\/+ skip=+\n\s*\/\/+ end=+$+ keepend fold contains=@Spell
-syn region  json5Comment        start="/\*"  end="\*/" fold contains=@Spell
+syn region  json5LineComment    start=+\/\/+ end=+$+ keepend contains=@Spell,json5Todo
+syn region  json5LineComment    start=+^\s*\/\/+ skip=+\n\s*\/\/+ end=+$+ keepend fold contains=@Spell,json5Todo
+syn region  json5Comment        start="/\*"  end="\*/" fold contains=@Spell,json5Todo
+
+syn keyword json5Todo           contained TODO FIXME XXX
 
 " Define the default highlighting
 hi def link json5String             String
@@ -66,6 +68,7 @@
 hi def link json5LineComment        Comment
 hi def link json5Comment            Comment
 hi def link json5NumError           Error
+hi def link json5Todo               Todo
 
 if !exists('b:current_syntax')
   let b:current_syntax = 'json5'