patch 9.1.0593: filetype: Asymptote files are not recognized

Problem:  filetype: Asymptote files are not recognized
Solution: detect '*.asy' files as asy filetype, include
          ftplugin and syntax plugin (AvidSeeker).

Reference: https://asymptote.sourceforge.io/

closes: #15252

Signed-off-by: AvidSeeker <avidseeker7@protonmail.com>
Signed-off-by: Christian Brabandt <cb@256bit.org>
diff --git a/runtime/doc/syntax.txt b/runtime/doc/syntax.txt
index 0bbba4d..2dfc5b6 100644
--- a/runtime/doc/syntax.txt
+++ b/runtime/doc/syntax.txt
@@ -958,6 +958,25 @@
 	:let g:filetype_asa = "aspvbs"
 	:let g:filetype_asp = "aspvbs"
 
+ASYMPTOTE					*asy.vim* *ft-asy-syntax*
+
+By default, only basic Asymptote keywords are highlighted. To highlight
+extended geometry keywords: >
+
+	:let g:asy_syn_plain = 1
+
+and for highlighting keywords related to 3D constructions: >
+
+	:let g:asy_syn_three = 1
+
+By default, Asymptote-defined colors (e.g: lightblue) are highlighted. To
+highlight TeX-defined colors (e.g: BlueViolet) use: >
+
+	:let g:asy_syn_texcolors = 1
+
+or for Xorg colors (e.g: AliceBlue): >
+
+	:let g:asy_syn_x11colors = 1
 
 BAAN						    *baan.vim* *baan-syntax*
 
diff --git a/runtime/doc/tags b/runtime/doc/tags
index 4e096ec..5c44174 100644
--- a/runtime/doc/tags
+++ b/runtime/doc/tags
@@ -6065,6 +6065,7 @@
 assert_report()	testing.txt	/*assert_report()*
 assert_true()	testing.txt	/*assert_true()*
 astro.vim	syntax.txt	/*astro.vim*
+asy.vim	syntax.txt	/*asy.vim*
 at	motion.txt	/*at*
 atan()	builtin.txt	/*atan()*
 atan2()	builtin.txt	/*atan2()*
@@ -7253,6 +7254,7 @@
 ft-aspperl-syntax	syntax.txt	/*ft-aspperl-syntax*
 ft-aspvbs-syntax	syntax.txt	/*ft-aspvbs-syntax*
 ft-astro-syntax	syntax.txt	/*ft-astro-syntax*
+ft-asy-syntax	syntax.txt	/*ft-asy-syntax*
 ft-awk-plugin	filetype.txt	/*ft-awk-plugin*
 ft-bash-syntax	syntax.txt	/*ft-bash-syntax*
 ft-basic-syntax	syntax.txt	/*ft-basic-syntax*
@@ -7299,7 +7301,9 @@
 ft-freebasic-plugin	filetype.txt	/*ft-freebasic-plugin*
 ft-freebasic-syntax	syntax.txt	/*ft-freebasic-syntax*
 ft-fvwm-syntax	syntax.txt	/*ft-fvwm-syntax*
+ft-gdscript-plugin	filetype.txt	/*ft-gdscript-plugin*
 ft-gitcommit-plugin	filetype.txt	/*ft-gitcommit-plugin*
+ft-go-plugin	filetype.txt	/*ft-go-plugin*
 ft-gprof-plugin	filetype.txt	/*ft-gprof-plugin*
 ft-groff-syntax	syntax.txt	/*ft-groff-syntax*
 ft-gsp-syntax	syntax.txt	/*ft-gsp-syntax*
@@ -7335,6 +7339,7 @@
 ft-masm-syntax	syntax.txt	/*ft-masm-syntax*
 ft-mathematica-syntax	syntax.txt	/*ft-mathematica-syntax*
 ft-matlab-indent	indent.txt	/*ft-matlab-indent*
+ft-mediawiki-syntax	syntax.txt	/*ft-mediawiki-syntax*
 ft-metafont	ft_mp.txt	/*ft-metafont*
 ft-metafont-intro	ft_mp.txt	/*ft-metafont-intro*
 ft-metafont-mappings	ft_mp.txt	/*ft-metafont-mappings*