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/ipkg.vim

@@ -0,0 +1,19 @@
+" Vim ftplugin file
+" Language:    Ipkg
+" Maintainer:  Idris Hackers (https://github.com/edwinb/idris2-vim), Serhii Khoma <srghma@gmail.com>
+" Last Change: 2024 Nov 05
+" Author:      ShinKage
+" License:     Vim (see :h license)
+" Repository:  https://github.com/ShinKage/idris2-nvim
+
+if exists("b:did_ftplugin")
+  finish
+endif
+
+setlocal comments=:--
+setlocal commentstring=--\ %s
+setlocal wildignore+=*.ibc
+
+let b:undo_ftplugin = "setlocal shiftwidth< tabstop< expandtab< comments< commentstring< iskeyword< wildignore<"
+
+let b:did_ftplugin = 1