Fix clock documentation typo.
Fix clock documentation typo.

oktayacikalin/pyglet,oktayacikalin/pyglet,oktayacikalin/pyglet,oktayacikalin/pyglet,mammadori/pyglet,mammadori/pyglet,theblacklion/pyglet,theblacklion/pyglet,oktayacikalin/pyglet,theblacklion/pyglet,mammadori/pyglet,mammadori/pyglet,theblacklion/pyglet,theblacklion/pyglet