Replace conditional import with import autoload

Avoid a repeat of #154, conditional imports are bad

Author: mmrwoods

after/plugin/fuzzbox.vim

@@ -14,9 +14,9 @@ if exists('g:loaded_glyph_palette') && !exists('g:fuzzbox_devicons_color_func')
     g:fuzzbox_devicons_color_func = 'glyph_palette#apply'
 endif
 
+import autoload '../../autoload/fuzzbox/internal/colors.vim'
 if exists('g:loaded_nerd_tree') && !exists('g:fuzzbox_devicons_color_func') &&
         findfile('after/syntax/nerdtree.vim', &rtp) =~ 'nerdtree-syntax-highlight'
-    import '../../autoload/fuzzbox/internal/colors.vim'
     runtime! after/syntax/nerdtree.vim
     map(colors.DeviconsColorTable(), (key, val) => {
         var ext = fnamemodify(key, ':e')