R1:1060736e895b

Fix some icons not displayed on UIExamples' "Icons and Images" (PHUIIconExample) page

Summary:
Fix three typos in icon names

Closes T15454

Test Plan: Go to `/uiexample/view/PHUIIconExample/` before and after applying the change; compare icons displayed for `fa-codiepie`, `fa-user-o`, `fa-thermometer-0`

Reviewers: O1 Blessed Committers, valerio.bozzolan

Reviewed By: O1 Blessed Committers, valerio.bozzolan

Subscribers: speck, tobiaswiese, valerio.bozzolan, Matthew, Cigaryno

Maniphest Tasks: T15454…