Add syntax folding for cmake

after/ftplugin/cmake.vim

@@ -1,17 +1,5 @@
-" TODO Create fold markers based on cmake syntax, eg.
-"
-"   if() <- open
-"   endif() <- close
-"
-"   foreach() <- open
-"   endforeach() <- close
-"
-" and so on for all other begin end style command pairs.
-"
-" Then change the setting.
-"
-"   setlocal foldmethod=syntax
-setlocal foldmethod=indent
+" Enable syntax folding, see .vim/after/syntax/cmake.vim
+setlocal foldmethod=syntax
 " Set comment string
 setlocal commentstring=#%s