Add restrict to pointers concept

[bobahop]

See this.

[wolf99]

This could also be referred to in the dynamic memory management concept.

[bobahop]

The original intent was to add it to the pointers concept. I wasn't up to doing it at the time, so it was requested to open an issue to add it to the pointer concept independently later on. Annnnnd.... the dynamic memory concept has been languishing for a while now. It doesn't need another reason for delay. 😄