move rustfmt on save into rust.vim

the way I had it set up before, it wasn't being run on neovim. Rustfmt
on save is not a part of ALE, it's just a part of the rust.vim plugin.

vim/ftplugin/rust.vim

@@ -1,3 +1,5 @@
+let g:rustfmt_autosave = 1
+
 nmap <F5> :Cargo run<CR>
 nmap <F7> :Cargo check<CR>
 nmap <F8> :Cargo test<CR>

vimrc

@@ -45,6 +45,7 @@ call vundle#begin()
   Plugin 'Glench/Vim-Jinja2-Syntax' " jinja2 syntax stuff
   Plugin 'rust-lang/rust.vim'       " bare minimum rust syntax stuff
   Plugin 'elubow/cql-vim'
+  Plugin 'tikhomirov/vim-glsl'
 
   " Past plugins
   "
@@ -481,7 +482,6 @@ let g:SuperTabClosePreviewOnPopupClose = 1
 if !has('nvim')
   let g:ale_linters = {'rust': ['analyzer']}
   let g:ale_fixers = {'rust': ['rustfmt', 'trim_whitespace', 'remove_trailing_lines']}
-  let g:rustfmt_autosave = 1
   let g:ale_rust_cargo_use_clippy = 1
   let g:ale_completion_enabled = 1
   set completeopt=menu,menuone,preview,noselect,noinsert