commands: Modify gen chromastyles to output all CSS classes

Chroma was updated to include a new function to output all CSS
classes without skipping any considered redundant with the current
style.

This will modify the `hugo gen chromastyles` command to use this new
function by default, which avoids potential problems if the style is
later modified.

Also includes requires the updated Chroma (v0.7.2).

Resolves #7167

commands/genchromastyles.go

@@ -68,7 +68,7 @@ func (g *genChromaStyles) generate() error {
 	if err != nil {
 		return err
 	}
-	formatter := html.New(html.WithClasses(true))
+	formatter := html.New(html.WithAllClasses(true))
 	formatter.WriteCSS(os.Stdout, style)
 	return nil
 }