Outline confusing/useless

When navigating RLS files, the Eclipse Outline tab shows some kind of parse tree that contains many elements that are meaningless to users. Some of them are unnamed. The outline should show a more meaningful structure of the rule. Single variables should never appear in the outline, but statements could be useful to list.

Start with the Eclipse Outline tab for RLS files and inspect how its current parse-tree elements are selected. Confirm the intended outline structure with maintainers, including whether statements should be listed and variables omitted; done means the outline presents meaningful rule elements without unnamed or standalone-variable entries.

Written by the indexing model from the issue text.