Only give relevant quick fixes w.r.t. "Remove unused ..."

[anthonyvdotbe]

See the image below. I did quick fix (Ctrl + .) on the variable x in the method run.

• quick fixes should be unique, there are several occurrences of Remove all unused imports and Remove unused import
• quick fixes should be useful: the occurrences of Remove unused import don't tell me which import
• quick fixes should apply to the yellow underlined element, so I'd expect only a single warning in this case: Remove unused "x"

[Achal1607]

Raised PR on netbeans: https://github.com/apache/netbeans/pull/7353