Specify a format when `git show` displays a commit

plug.vim

@@ -1934,7 +1934,7 @@ function! s:preview_commit()
   execute 'pedit' sha
   wincmd P
   setlocal filetype=git buftype=nofile nobuflisted
-  execute 'silent read !cd' s:shellesc(g:plugs[name].dir) '&& git show' sha
+  execute 'silent read !cd' s:shellesc(g:plugs[name].dir) '&& git show --pretty=medium' sha
   normal! gg"_dd
   wincmd p
 endfunction