Remove remaining vim artifacts after migration to neovim

.config/nvim/init.vim_

@@ -1,3 +0,0 @@
-set runtimepath^=~/.vim runtimepath+=~/.vim/after
-let &packpath = &runtimepath
-source ~/.vimrc

.vim/snippets/vimwiki.snippets

@@ -1,5 +0,0 @@
-snippet ddd
-	= `strftime("%-d. %b:")` ${1:summary} =
-	%% `strftime("%Y-%m-%d")`
-
-	${0}