Improve checkhealth output

- Don't list all bad highlight groups, they might be too many to list.
  Instead tell the user how to list them
- The colorscheme may not be at fault for bad highlight groups, instead
  they may come from plugins that define their own highlight groups.
  Therefore avoid naming the current colorscheme specifically.

Author: vimpostor

lua/tpipeline/health.lua

@@ -24,9 +24,7 @@ M.check = function()
 	end
 
 	if info.bad_colors > 0 then
-		local groups = vim.fn['tpipeline#debug#get_bad_hl_groups']()
-		local colorscheme = vim.api.nvim_exec2("colorscheme", {output = true}).output
-		vim.health.report_warn(string.format("The colorscheme %s contains %d highlight groups that don't properly support truecolor. These colors might not render correctly in tmux.\nBad highlight groups are: %s", colorscheme, info.bad_colors, vim.inspect(groups)))
+		vim.health.report_warn(string.format("The current colorscheme contains %d highlight groups that don't properly support truecolor.\nThese colors might not render correctly in tmux.\nYou can list them with \":echom tpipeline#debug#get_bad_hl_groups()\".", info.bad_colors))
 	else
 		vim.health.report_ok("Colorscheme has true color support")
 	end