Specify the SDG title uses two lines

This way translators will find a hint indicating they must use two lines
and not three or more, since the title is optimized for being displayed
in two lines.

app/components/sdg/goals/show_component.rb

@@ -21,6 +21,6 @@ class SDG::Goals::ShowComponent < ApplicationComponent
     end
 
     def split_title
-      safe_join(goal.multiline_title.split("\n").map { |text| tag.span(text) }, " ")
+      safe_join(goal.title_in_two_lines.split("\n").map { |text| tag.span(text) }, " ")
     end
 end