update gitgutter signs

plug-config/gitgutter.vim

@@ -1,10 +1,11 @@
 
 
-let g:gitgutter_sign_added              = '⏽'
-let g:gitgutter_sign_modified           = '⏽'
+let g:gitgutter_sign_added              = '▎'
+let g:gitgutter_sign_modified           = '▎'
 let g:gitgutter_sign_removed            = '契'
 let g:gitgutter_sign_removed_first_line = '契'
-let g:gitgutter_sign_modified_removed   = '⏽'
+let g:gitgutter_sign_modified_removed   = '▎'
+let g:gitgutter_preview_win_floating = 1
 
 let g:gitgutter_enabled = 1