runtime(kdl): include syntax, indent and ftplugin files

closes: #14956

Co-authored-by: Aram Drevekenin <aram@poor.dev>
Signed-off-by: inzuo Jiang <jiangyinzuo@foxmail.com>
Signed-off-by: Christian Brabandt <cb@256bit.org>

runtime/syntax/kdl.vim

@@ -0,0 +1,45 @@
+" Vim syntax file
+" Language: KDL
+" Maintainer: Aram Drevekenin <aram@poor.dev>
+" Maintainer: Yinzuo Jiang <jiangyinzuo@foxmail.com>
+" Latest Revision: 2024-06-10
+
+" quit when a syntax file was already loaded
+if exists("b:current_syntax")
+  finish
+endif
+
+syn match kdlNode '\v(\w|-|\=)' display
+syn match kdlBool '\v(true|false)' display
+
+syn keyword kdlTodo contained TODO FIXME XXX NOTE
+syn match kdlComment "//.*$" contains=kdlTodo
+
+" Regular int like number with - + or nothing in front
+syn match kdlNumber '\d\+'
+syn match kdlNumber '[-+]\d\+'
+
+" Floating point number with decimal no E or e (+,-)
+syn match kdlNumber '\d\+\.\d*' contained display
+syn match kdlNumber '[-+]\d\+\.\d*' contained display
+ 
+" Floating point like number with E and no decimal point (+,-)
+syn match kdlNumber '[-+]\=\d[[:digit:]]*[eE][\-+]\=\d\+' contained display
+syn match kdlNumber '\d[[:digit:]]*[eE][\-+]\=\d\+' contained display
+ 
+" Floating point like number with E and decimal point (+,-)
+syn match kdlNumber '[-+]\=\d[[:digit:]]*\.\d*[eE][\-+]\=\d\+' contained display
+syn match kdlNumber '\d[[:digit:]]*\.\d*[eE][\-+]\=\d\+' contained display
+
+syn region kdlString start='"' end='"' skip='\\\\\|\\"' display
+ 
+syn region kdlChildren start="{" end="}" contains=kdlString,kdlNumber,kdlNode,kdlBool,kdlComment
+
+hi def link kdlTodo        Todo
+hi def link kdlComment     Comment
+hi def link kdlNode        Statement
+hi def link kdlBool        Boolean
+hi def link kdlString      String
+hi def link kdlNumber      Number
+
+let b:current_syntax = "kdl"