Set a highlight group. TODO: ns_id = 0, should modify :highlight namespace TODO val should take update vs reset flag Parameters: ~ {ns_id} number of namespace for this highlight {name} highlight group name, like ErrorMsg {val} highlight definiton map, like |nvim_get_hl_by_name|. in addition the following keys are also recognized: default : don't override existing definition, like hi default ctermfg : sets foreground of cterm color ctermbg : sets background of cterm color cterm : cterm attribute map. sets attributed for cterm colors. similer to hi cterm Note: by default cterm attributes are same as attributes of gui color