Added `overflow-x` property to pre base styles
Added `overflow-x` property to pre base styles

Summary:
Found this when testing tota11y on the github landing page :)

Test Plan:
. View the tota11y landing page
. Activate the link text plugin
. See that alt suggestion overflow is hidden behind a scrollbar

Auditors: riley

Khan/tota11y,Khan/tota11y,dudeOFprosper/tota11y,dudeOFprosper/tota11y