runtime(idris2): include filetype,indent+syntax plugins for (L)Idris2 + ipkg

closes: #15993

Co-authored-by: Christian Clason <ch.clason+github@icloud.com>
Signed-off-by: Serhii Khoma <srghma@gmail.com>
Signed-off-by: Christian Brabandt <cb@256bit.org>

runtime/syntax/ipkg.vim

@@ -0,0 +1,66 @@
+" Vim syntax file
+" Language:    Ipkg
+" Maintainer:  Idris Hackers (https://github.com/edwinb/idris2-vim), Serhii Khoma <srghma@gmail.com>
+" Last Change: 2020 May 19
+" Version:     0.1
+" Author:      ShinKage
+" License:     Vim (see :h license)
+" Repository:  https://github.com/ShinKage/idris2-nvim
+"
+" Syntax highlight for Idris 2 Package Descriptors (idris-lang.org)
+"
+
+if exists("b:current_syntax")
+  finish
+endif
+
+" we want to use line continuations (\) BEGINNING
+let s:cpo_save = &cpo
+set cpo&vim
+
+syn keyword ipkgKey
+    \ package
+    \ authors
+    \ maintainers
+    \ license
+    \ brief
+    \ readme
+    \ homepage
+    \ sourceloc
+    \ bugtracker
+    \ options
+    \ opts
+    \ sourcedir
+    \ builddir
+    \ outputdir
+    \ prebuild
+    \ postbuild
+    \ preinstall
+    \ postinstall
+    \ preclean
+    \ postclean
+    \ version
+    \ langversion
+    \ modules
+    \ main
+    \ executable
+    \ depends
+
+" we want to use line continuations (\) END
+let &cpo = s:cpo_save
+unlet s:cpo_save
+
+syn region ipkgString start=+"+ skip=+\\\\\|\\"+ end=+"+ contains=@Spell
+syn match ipkgVersion "[0-9]*\([.][0-9]*\)*"
+syn match ipkgName "[a-zA-Z][a-zA-z0-9_']*\([.][a-zA-Z][a-zA-z0-9_']*\)*" contained
+syn match ipkgOperator "\(,\|&&\|<\|<=\|==\|>=\|>\)"
+syn match ipkgComment "---*\([^-!#$%&\*\+./<=>\?@\\^|~].*\)\?$" contains=@Spell
+
+highlight def link ipkgKey Statement
+highlight def link ipkgString String
+highlight def link ipkgVersion Number
+highlight def link ipkgName Identifier
+highlight def link ipkgOperator Operator
+highlight def link ipkgComment Comment
+
+let b:current_syntax = "ipkg"