R1:a4e57800431f

Remove "Search Preferences"

Summary:
Ref T4103. This removes these options:

{F1660585}

The jump nav option came from T916, when we had a separate jump nav on the home page. Essentially no one has ever been confused by the behavior of search or disabled this feature. Here are the stats for this install:

| Total Users | 36656 |
| Have Set Any Preference | 3084 |
| Have Disabled Jump | 6
| Are Not "Security Researchers" | 2
| Any Account Activity | 0

The "/" option came in the same change, but the…