Extra `syntax clear` possibly messing up colorscheme

[TheWall89]

Hi,

we have some problem in making your syntax for YAML work with the Dracula vim theme: dracula/vim#163
@dsifford , @benknoble

After some research, we believe the problem lays in line 20 of your syntax file:

vim-yaml/after/syntax/yaml.vim

Line 20 in 8fc9136

syntax clear

If we remove that line, we are able to color your defined groups. Is it a leftover from a development/debug session?

Ps. This also affects sheerun/vim-polyglot @sheerun