Add meaning of green colored memory blocks for "GPU Shared RAM" to doc

[thomasegriffith]

Is your feature request related to a problem? Please describe.
Please add the meaning of the green colored memory blocks in the "GPU Shared RAM" section of the documentation. It only talks about the memory blocks colored in "grey", so I have no idea what the memory displayed in "green" means.

The doc states "GPU Shared RAM Status Shared GPU. (In grey the used memory)".

Describe the solution you'd like
I'd like to see what "grey" vs "green" means.

Describe alternatives you've considered
Googling yields nothing.

Additional context
See screenshot.