patch 9.1.0425: filetype: purescript files are not recognized

Problem:  filetype: purescript files are not recognized
Solution: recognize '*.purs' files as purescript filetype,
          include basic purescript filetype plugin
          (Riley Bruins)

Reference: https://github.com/purescript/documentation/blob/master/language/Syntax.md#comments

closes: #14813

Signed-off-by: Riley Bruins <ribru17@hotmail.com>
Signed-off-by: Christian Brabandt <cb@256bit.org>

.github/MAINTAINERS

@@ -200,6 +200,7 @@ runtime/ftplugin/postscr.vim		@mrdubya
 runtime/ftplugin/prisma.vim		@ribru17
 runtime/ftplugin/ps1.vim		@heaths
 runtime/ftplugin/ps1xml.vim		@heaths
+runtime/ftplugin/purescript.vim		@ribru17
 runtime/ftplugin/pymanifest.vim		@ObserverOfTime
 runtime/ftplugin/python.vim		@tpict
 runtime/ftplugin/qb64.vim		@dkearns

runtime/filetype.vim

@@ -1866,6 +1866,9 @@ au BufNewFile,BufRead *.pk			setf poke
 " Protocols
 au BufNewFile,BufRead */etc/protocols		setf protocols
 
+" Purescript
+au BufNewFile,BufRead *.purs			setf purescript
+
 " PyPA manifest files
 au BufNewFile,BufRead MANIFEST.in		setf pymanifest
 

runtime/ftplugin/purescript.vim

@@ -0,0 +1,14 @@
+" Vim filetype plugin
+" Language:	purescript
+" Maintainer:	Riley Bruins <ribru17@gmail.com>
+" Last Change:	2024 May 19
+
+if exists('b:did_ftplugin')
+  finish
+endif
+let b:did_ftplugin = 1
+
+setl comments=s1f:{-,mb:\ ,ex:-},:--\ \|,:--
+setl commentstring=--\ %s
+
+let b:undo_ftplugin = 'setl com< cms<'

src/testdir/test_filetype.vim

@@ -577,6 +577,7 @@ def s:GetFilenameChecks(): dict<list<string>>
     psl: ['file.psl'],
     pug: ['file.pug'],
     puppet: ['file.pp'],
+    purescript: ['file.purs'],
     pymanifest: ['MANIFEST.in'],
     pyret: ['file.arr'],
     pyrex: ['file.pyx', 'file.pxd'],

src/version.c

@@ -704,6 +704,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    425,
 /**/
     424,
 /**/