Add snippets for rust

vim/ftplugin/rust.vim

@@ -8,3 +8,5 @@ let g:ale_fix_on_save=1
 
 nnoremap <F5> :w<cr>:!cargo run<cr>
 nnoremap <F6> :w<cr>:!cargo test<cr>
+
+nnoremap <F8> ^wimut <esc>

vim/neosnippets/rust.snip

@@ -0,0 +1,4 @@
+snippet     debug
+abbr        deb
+options     head
+    println!("{:?}", ${1});