[Policy, no patch] Never require descriptions if a title/label is already required

Only add descriptive text under form elements when they would be unclear without them. Try to make the form label clear by itself.

This is what our Interface test UI standards say about form elements. I believe it is a good idea to apply this standard to Drupal globally. Two examples of where this problem occurs in core are #1911768: Make token and token type descriptions optional → , and the Simpletest test browser, which throws PHP errors if test cases have a title, but no description.

My suggestion for a policy: Additional descriptions should always be optional, as human-readable titles/labels are ideally descriptive enough. Only when this is not possible, should extra descriptions be added. Code that depends on descriptions being set should therefore be fixed to remove this dependency.