patch 9.1.0453: filetype: rasi files are not recognized

Problem:  filetype: rasi files are not recognized
Solution: regonize '*.rasi' files as rasi filetype,
          include a filetype and syntax plugin
          (Pierrick Guillaume)

ported from: https://github.com/Fymyte/rasi.vim

closes: #14821

Signed-off-by: Pierrick Guillaume <pierguill@gmail.com>
Signed-off-by: Christian Brabandt <cb@256bit.org>
diff --git a/.github/MAINTAINERS b/.github/MAINTAINERS
index fd80c53..dbc0486 100644
--- a/.github/MAINTAINERS
+++ b/.github/MAINTAINERS
@@ -209,6 +209,7 @@
 runtime/ftplugin/qb64.vim		@dkearns
 runtime/ftplugin/qml.vim		@ChaseKnowlden
 runtime/ftplugin/racket.vim		@benknoble
+runtime/ftplugin/rasi.vim		@fymyte
 runtime/ftplugin/readline.vim		@dkearns
 runtime/ftplugin/rescript.vim		@ribru17
 runtime/ftplugin/routeros.vim		@zainin
@@ -479,6 +480,7 @@
 runtime/syntax/raml.vim			@in3d
 runtime/syntax/rapid.vim		@KnoP-01
 runtime/syntax/ratpoison.vim		@trapd00r
+runtime/syntax/rasi.vim			@fymyte
 runtime/syntax/rc.vim			@chrisbra
 runtime/syntax/rcs.vim			@hdima
 runtime/syntax/rebol.vim		@mrdubya