Issue 239: minor doc typo fix.
Issue 239: minor doc typo fix.

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