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/ftplugin/idris2.vim

@@ -0,0 +1,34 @@
+" Vim ftplugin file
+" Language:	   Idris 2
+" Last Change: 2024 Nov 05
+" Maintainer:  Idris Hackers (https://github.com/edwinb/idris2-vim), Serhii Khoma <srghma@gmail.com>
+" License:     Vim (see :h license)
+" Repository:  https://github.com/ShinKage/idris2-nvim
+"
+" Based on ftplugin/idris2.vim from https://github.com/edwinb/idris2-vim
+
+if exists("b:did_ftplugin")
+  finish
+endif
+
+setlocal shiftwidth=2
+setlocal tabstop=2
+
+" Set g:idris2#allow_tabchar = 1 to use tabs instead of spaces
+if exists('g:idris2#allow_tabchar') && g:idris2#allow_tabchar != 0
+  setlocal noexpandtab
+else
+  setlocal expandtab
+endif
+
+setlocal comments=s1:{-,mb:-,ex:-},:\|\|\|,:--
+setlocal commentstring=--\ %s
+
+" makes ? a part of a word, e.g. for named holes `vzipWith f [] [] = ?vzipWith_rhs_3`, uncomment if want to reenable
+" setlocal iskeyword+=?
+
+setlocal wildignore+=*.ibc
+
+let b:undo_ftplugin = "setlocal shiftwidth< tabstop< expandtab< comments< commentstring< iskeyword< wildignore<"
+
+let b:did_ftplugin = 1