runtime(lex): include lex ftplugin file

Spec found [here](https://docs.oracle.com/cd/E19504-01/802-5880/lex-6/index.html)

closes: #15174

Signed-off-by: Riley Bruins <ribru17@hotmail.com>
Signed-off-by: Christian Brabandt <cb@256bit.org>
diff --git a/.github/MAINTAINERS b/.github/MAINTAINERS
index 0320e21..d0a75f9 100644
--- a/.github/MAINTAINERS
+++ b/.github/MAINTAINERS
@@ -187,6 +187,7 @@
 runtime/ftplugin/kivy.vim		@ribru17
 runtime/ftplugin/kotlin.vim		@udalov
 runtime/ftplugin/less.vim		@genoma
+runtime/ftplugin/lex.vim		@ribru17
 runtime/ftplugin/liquid.vim		@tpope
 runtime/ftplugin/lua.vim		@dkearns
 runtime/ftplugin/lc.vim			@ribru17
diff --git a/runtime/ftplugin/lex.vim b/runtime/ftplugin/lex.vim
new file mode 100644
index 0000000..c6c47fe
--- /dev/null
+++ b/runtime/ftplugin/lex.vim
@@ -0,0 +1,14 @@
+" Vim filetype plugin
+" Language:	Lex and Flex
+" Maintainer:	Riley Bruins <ribru17@gmail.com>
+" Last Change:	2024 Jul 06
+
+if exists('b:did_ftplugin')
+  finish
+endif
+let b:did_ftplugin = 1
+
+setlocal comments=sO:*\ -,mO:*\ \ ,exO:*/,s1:/*,mb:*,ex:*/,://
+setlocal commentstring=//\ %s
+
+let b:undo_ftplugin = 'setl com< cms<'