Use safer sign for removed line

dotfiles/vim/vimrc

@@ -17,7 +17,7 @@ set statusline+=%*
 
 let g:gitgutter_sign_added = '✚'
 let g:gitgutter_sign_modified = '❱'
-let g:gitgutter_sign_removed = '❌'
+let g:gitgutter_sign_removed = 'x'
 let g:gitgutter_sign_removed_first_line = '^'
 let g:gitgutter_sign_modified_removed = '❰'