runtime(astro): Add filetype, syntax and indent plugin

related: #14558
closes: #14561

ported from: https://github.com/wuelnerdotexe/vim-astro

Signed-off-by: Philip H <47042125+pheiduck@users.noreply.github.com>
Signed-off-by: Christian Brabandt <cb@256bit.org>
diff --git a/runtime/doc/syntax.txt b/runtime/doc/syntax.txt
index 0688575..619046e 100644
--- a/runtime/doc/syntax.txt
+++ b/runtime/doc/syntax.txt
@@ -1,4 +1,4 @@
-*syntax.txt*	For Vim version 9.1.  Last change: 2024 Apr 13
+*syntax.txt*	For Vim version 9.1.  Last change: 2024 Apr 21
 
 
 		  VIM REFERENCE MANUAL	  by Bram Moolenaar
@@ -930,6 +930,21 @@
 nasm_ctx_outside_macro	contexts outside macro not as Error
 nasm_no_warn		potentially risky syntax not as ToDo
 
+ASTRO						*astro.vim* *ft-astro-syntax*
+
+Configuration
+
+The following variables control certain syntax highlighting features.
+You can add them to your .vimrc: >
+	let g:astro_typescript = "enable"
+<
+Enables TypeScript and TSX for ".astro" files. Default Value: "disable" >
+	let g:astro_stylus = "enable"
+<
+Enables Stylus for ".astro" files. Default Value: "disable"
+
+NOTE: You need to install an external plugin to support stylus in astro files.
+
 
 ASPPERL and ASPVBS			*ft-aspperl-syntax* *ft-aspvbs-syntax*
 
@@ -6118,5 +6133,4 @@
 		many places.
 "<\@1<=span"	Matches the same, but only tries one byte before "span".
 
-
  vim:tw=78:sw=4:ts=8:noet:ft=help:norl: