Reproduction steps:
1. Open new project
2. Go Edit -> Project Settings -> Input
3. Expand Axes -> Horizontal
4. Hover over "Negative button" and "Positive button"

Expected: Negative button - "The button used to push the axis in the negative direction."; Positive button - "The button used to push the axis in the positive direction."
Actual: Negative button - "Button to be pressed for movement in positive direction."; Positive button - "Button to be pressed for movement in negative direction."

Reproduced on: 5.5.4p4; 5.6.3p2; 2017.1.1f1; 2017.2.0b10; 2017.3.0a6

Note: Actual result from https://docs.unity3d.com/Manual/ConventionalGameInput.html