Use vim-coiled-snake instead of custom Python fold

vimrc

@@ -171,6 +171,9 @@ let g:DoxygenToolkit_commentType = 'C++'
 let g:markdown_fenced_languages =
   \ ['cpp', 'c', 'cmake', 'sh', 'vim', 'python', 'yaml']
 
+" Python folding
+Plug 'kalekundert/vim-coiled-snake'
+
 " Enable builtin syntax folding
 let g:xml_syntax_folding = 1
 let g:sh_fold_enabled = 1