Update annotations of engine projectile methods

[Garanas]

Description of the proposed changes

Document the support for method chaining of the projectile engine methods. I noticed this behavior as I was working on #6398.

Testing done on the proposed changes

I called every function and checked the output of the log with logging the instance. If the references match then the function supports method chaining.

LOG(self) -- returns memory reference
LOG("ChangeDetonateAboveHeight", self:ChangeDetonateAboveHeight(0)) -- returns nil
LOG("SetLifetime", self:SetLifetime(10)) -- returns memory reference

Checklist

• Changes are annotated, including comments where useful
• Changes are documented in the changelog for the next game version