Noise2d update

[takyano]

Fixes #1047

Changes:

• Remove extra * (asterisk) in description comment
• Change text description for second noise example matches actual parameters used.
• Increase framerate of example by writing to the pixels array.

The original version: Noise2D Example at 2 SPF (Seconds Per Frame)

The faster version: Noise2d Pull

Screenshots of the change:

It should look the same, just faster.