Use an autoformat plugin for everything.

autoformat.vim

@@ -0,0 +1,4 @@
+au BufWrite * :Autoformat
+" see here for instructions to get scalafmt set up
+let g:formatdef_scalafmt = '"ng-nailgun scalafmt"'
+let g:formatters_scala = ['scalafmt']

ftplugin/rust.vim

@@ -1 +1,2 @@
-let g:autofmt_autosave = 1
+let g:formatdef_rustfmt_force = '"rustfmt --force"'
+let g:formatters_rust = ['rustfmt_force']

plug.vim

@@ -45,6 +45,9 @@ Plug 'vim-scripts/groovy.vim'
 Plug 'vim-scripts/groovyindent-unix'
 " LSP
 Plug 'autozimu/LanguageClient-neovim', {'tag': 'binary-*-x86_64-unknown-linux-musl'}
+" auto format all the things
+" https://github.com/Chiel92/vim-autoformat
+Plug 'Chiel92/vim-autoformat'
 
 " All of your Plugins must be added before the following line
 call plug#end()            " required

vimrc

@@ -16,6 +16,7 @@ source mapping.vim
 source jsonnet.vim
 source racer.vim
 source lsp.vim
+source autoformat.vim
 exec "cd " . oldwd
 
 " turn on file type plugins