Browse issues titles should link to /issues with section selected

[miketaylr]

I.e., if I click on "Needs Diagnosis" from the home page I should end up at /issues with the "needsdiagnosis" filter button selected and the appropriate filter applied on results.

[miketaylr]

To be clear, both the key and the section header should be clickable.

[karlcow]

Agreed.

[miketaylr]

This was deployed to master.