added rust lsp support

vim/.vim/after/ftplugin/rust.vim

@@ -0,0 +1,17 @@
+syntax enable
+filetype plugin indent on
+set omnifunc=ale#completion#OmniFunc
+" set omnifunc+=syntaxcomplete#Complete
+" set omnifunc=ale#completion#Complete
+
+let g:ale_completion_enabled = 1
+let g:ale_completion_autoimport = 1
+let g:ale_sign_column_always = 1
+let g:ale_fix_on_save = 1
+
+" The following lines are needed to provide compatibility between
+" rust-analyzer and ALE. When this is not included ALE omnifunc completion
+" locks up completely at autocomplete
+let g:ale_fixers = { 'rust': ['rustfmt', 'trim_whitespace', 'remove_trailing_lines'] }
+let g:ale_rust_rls_executable = 'rust-analyzer'
+let g:ale_rust_rls_toolchain = ''