'Go To Definition' link still remains active when navigated to the definition.

Created by: amarsiingh

• Sourcegraph version: 3.2 or latest
• Platform information: macOS Mojave 10.14.3, Google Chrome Version 72.0.3626.121 (Official Build) (64-bit)

Steps to reproduce:

1. Go to a source file and tap on a variable/function name.
2. In the exploring popup, tap 'Go To Definition' option.

Expected behavior:

• When at the root of the of definition, 'Go To Definition' option should be inactive or hidden, to indicate root of the search navigation.

Actual behavior:

• 'Go To Definition' option is still active, and tapping on it doesn't have any effect.